eptatretus deani , known as the black hagfish , is a species of hagfish .

common to other species of hagfish , their unusual feeding habits and slime-producing capabilities have led members of the scientific and popular media to dub the hagfish as the most " disgusting " of all sea creatures .

although hagfish are sometimes called " slime eels " , they are not eels at all .

black hagfish

another hagfish species that may occur in california is the black hagfish ( eptatretus deani ) ; it is found in deeper water , is darker in coloration ( purplish black ) , and has a shorter head in proportion to the body .
a mongoose is lightning fast and has razor - sharp teeth . a black mamba can kill 15 grown men with just one bite . which of these two mortal enemies will win ?
hagfish lack bones , paired fins , and a true jaw . the hagfish skeleton is composed of
14 . hagfish are threatened from both intentional fishing and unintentional bycatch . hagfish weren’t always fished , but because several more preferable fish species are overfished and hard to catch , fishermen have moved down to catching hagfish .
a mature pacific hagfish female will produce between 20 - 30 eggs per reproductive cycle . there is no known reproductive season or cycle length for hagfish .
the slime could also give the hagfish a competitive edge among other scavengers . if many hagfish were feeding off zintzen’s bait , it soon became draped in slime . the mucus puts off fish competitors , allowing the hagfish to monopolise their morsels .
thought the hagfish day was the 19th of oct . enjoyed reading this ! ~
don ' t worry the hagfish is not hurt , it ' s just anaesthetised .
the hagfish is preyed upon by some marine mammals and large sea living invertebrates . most animals do however stay away from the hagfish since they risk being suffocated by the slime .
pacific hagfish - eptatretus stoutii the hagfish can tie itself into a knot . source : aquarium of the pacific intended audience : general reading level : middle school teacher section : yes
the hagfish eats marine worms and other invertebrates . it has a very low metabolism and can go for as long as seven months without eating . newly hatched hagfish are miniature copies of the adult hagfish . the hagfish is found in cold ocean waters in the northern and southern hemispheres . it is found on muddy sea floors and may live in very large groups of up to 15 , 000 individuals . there are about 60 species of hagfish .
pacific hagfish are not currently exhibited . this information is supplied for use as a reference .
pacific hagfish - eptatretus stoutii the pacific hagfish is also known as the slime eel . source : monterey bay aquarium intended audience : general reading level : middle school teacher section : yes
the metabolism of the hagfish is remarkably slow and up to seven months can pass between meals .
“ atlantic hagfish ” , sea and sky . retrieved on 2008 - 03 - 28 . urltoken
10 . this slime gives hagfish a slippery exit when attacked by predators . a larger fish looking for a meal instead gets a mouth full of slime , while the hagfish can slide away .
we are developing standard procedures for sampling hagfish landed by commercial fisheries and collected during scientific surveys .
table 29 . 1 . recreational and commercial landings of atlantic hagfish ( thousand metric tons ) .
forster , m . e . ( 1990 ) confirmation of the low metabolic rates of hagfish .
shelton , r . g . j . ( 1978a ) of hagfish , goats and sprats .
the pacific hagfish is listed on the iucn red list as “data deficient , more research needed” to quantify the impacts of fishing on the population of this species . the red list states : “this species is only known from the northeastern pacific where it is heavily targeted in at least half of range for the asian eel - skin leather market , ( wallets , leather , and boots ) . reported landings for this species are mixed with the black hagfish ( e . deani ) and have been quite variable in both total catch and effort over the past 20 years . the reasons for the variability in catch and effort trends are not well understood . ”
commercial interest has developed in pacific ( eptatretus stoutii ) and black hagfish ( e . deani ) in southeast alaska with information lacking to properly develop a fishery . currently , the fishery is targeted using a commissioner’s permit in which the alaska department of fish game decides harvest level , gear type , season , etc to prosecute the fishery . the primary market is freezing hagfish in blocks and / or shipping them live to korea . little is known on both species life history within southeast alaska including : distribution , size at maturity , fecundity , sex ratio , length and weight frequencies . preliminary life history information will be collected on experimental longline trap sets .
atlantic hagfish - myxine glutinosa the atlantic hagfish is found on both sides of the north atlantic ocean . source : sea and sky intended audience : student reading level : middle school teacher section : no
in asia , over fishing has led to a significant decrease in the local hagfish population and asian fisheries have therefore begun to show an interest in the hagfish populations in the atlantic . while this might be beneficial for local economies along the atlantic coasts , it could also pose a threat to the atlantic hagfish population . care and caution must be exercised unless we wish to see the atlantic hagfish population go the same way as the asian one . as mentioned above , studies indicate that the hagfish female only produces a low number of eggs each breeding period and hagfish are therefore extra sensitive to over - fishing .
braun , c . b . ( 1994 ) a novel cutaneous sensory system in hagfish . soc .
where present at high densities , hagfish burrowing and feeding activities have a significant impact on substrate turnover .
hagfish are significant as predators on benthic invertebrates and , in some cases , mesopelagic invertebrates and vertebrates .
when studied , hagfish females have produce up to 30 yolky one inch long eggs with tough shells . if this low number is true for all hagfish , it means that it might take a long time for a hagfish population to recover when harmed , e . g . by over - fishing or pollution .
in most parts of the world hagfish is viewed as a useless by - catch , but there are a few countries in south east asia where hagfish is appreciated on the dinner table . nearly 5 million pounds ( 2 268 000 kg ) of hagfish meat is for instance consumed in south korea each year .
justification : this species is only known from the northeastern pacific , where it is heavily targeted in at least half of range for the asian eel - skin leather market . reported landings for this species are mixed with the black hagfish ( e . deani ) and have been quite variable in both total catch and effort over the past 20 years ( 1988 - 2007 ) . the reasons for the variability in catch and effort trends are not well understood . this species is therefore currently listed as data deficient . more research is needed to quantify the impacts of fishing on this species population .
although a hagfish fishery exists in the gulf of maine , the resource is not actively managed at present .
fernholm , b . and holmberg , k . ( 1975 ) the eyes in three genera of hagfish (
the hagfish needs the salinity in its habitat to be stable , because these fishes have virtually no osmoregulation and are therefore highly vulnerable to salinity changes . the hagfish is the only known vertebrate with body fluids isosomotic with seawater . this means that the body fluids of the hagfish have the same total osmotic pressure or osmolality as seawater .
ps it’s sad that this paper didn’t come out on october 16 th , which was designated as hagfish day .
hagfish adults , juveniles , and eggs can represent a significant prey item for marine mammals and large predatory invertebrates .
slip ' n ' slime . the slime that an annoyed hagfish oozes through its skin can fill a bucket .
hagfish are found in temperate seas in both hemispheres , but hagfish has not been found in the red sea . a majority of the species live in rather cold environments where the water is at least 20 meters ( 66 feet ) deep . when hagfish live in warmer parts of the world , they are normally only found in really deep waters . hagfish can survive at remarkable depths and have been found 1700 metres ( 5600 feet ) down into the ocean .
in the western pacific ocean a fishery for hagfish has existed since world war ii . overharvesting lead to the expansion of hagfish fisheries into the eastern pacific off the northwestern us and british columbia , and then during the late 1980’s to the mid 1990’s to the western atlantic off of maritime canada and new england . hagfish are utilized as a food source and their skins are valued for leather products . all hagfish are exported whole to korea ( nefsc 2003 ) .
pacific hagfish - eptatretus stoutii hagfish have been around , mostly unchanged , since the paleozoic era 450 million years ago . source : california department of fish and wildlife intended audience : general reading level : middle school teacher section : yes
the inshore hagfish , eptatretus burge , is listed on the iucn red list as near threatened . this hagfish species is commonly found in the western north pacific off the coasts of southern japan , south korea , northern , and northwestern taiwan . in these geographic locations hagfish is a native ( endemic ) species . they are very heavily fished in the china sea for their skin and for food . approximately five million pounds of hagfish meat is eaten yearly in korea .
hagfish represent one of the most important mechanisms for the rapid cleanup and processing of carrion - falls . in areas subject to intensive commercial fisheries , hagfish probably play a key role in the removal and recycling of discarded by - catch .
munz , f . w . and morris , r . w . ( 1965 ) metabolic rate of the hagfish ,
us navy scientists have produced a synthetic version of hagfish slime that they hope to use in protective gear for troops .
dining in . hagfish swarm to a corpse and bury themselves in it before eating their way out with their skin .
a data collection program has been proposed for atlantic hagfish by nmfs requiring seafood dealers to acquire permits and report on the purchase of hagfish made from commercial fishing vessels to aid in the future management of this species ( federal register 2006 ) .
all these interesting properties make hagfish slime dead useful for lots of potential applications . there’s even an online recipe for scones made with hagfish slime—courtesy of the museum of awful food—for the culinarily adventurous . the slime is a handy substitute for egg whites . ( by the way , that trendy “eel skin” wallet or purse in your collection might actually be hagfish leather . )
the tough and soft skin of the hagfish is also a popular commodity and is used to make wallets , purses , handbags , boots and similar items . the skin is normally market under the name “eelskin” or “eel skin” , not hagfish skin .
a hagfish usually swims slowly along the seafloor in a snake - like fashion although it may have occasional bursts of speed .
mcinerney , j . e . and evans , d . o . ( 1970 ) habitat characteristics of the pacific hagfish ,
hall - arber , m . ( 1996 ) workshop probes hagfish processing potential in us : fishery discards worry fishermen . in
martini , f . h . and heiser , j . b . ( 1989 ) field observations on the atlantic hagfish ,
wisner , r . l . and mcmillan , c . b . ( 1988 ) a new species of hagfish , genus
pacific hagfish - eptatretus stoutii hagfish eat worms and invertebrates , but they also enter both dying and dead fish and eat them from the inside out . source : oregon coast aquarium intended audience : general reading level : middle school teacher section : yes
” disgusting hagfish and magnificent sharks ” , tammy frank , noaa ocean explorer . retrieved on 2008 - 03 - 28 . urltoken
it is estimated that hagfish may live 40 years in the ocean and 17 years in a protected environment such as an aquarium .
dorsal spines ( total ) : 0 ; dorsal soft rays ( total ) : 0 ; anal spines : 0 ; anal soft rays : 0 . no true fins - one dorsal finfold , far back , median , very low , continuous with the caudal ; caudal moderately broad , and round with ray - like markings ; ventral finfold very low , origin somewhat posterior to last gill aperture , extending to anus ( ref . 6885 ) . prune colored , preserved specimens black ; frequently piebald with light spots ; the very edges of caudal and ventral finfolds may be light colored ( ref . 6885 ) .
dorsal spines ( total ) : 0 ; dorsal soft rays ( total ) : 0 ; anal spines : 0 ; anal soft rays : 0 . no true fins - one dorsal finfold , far back , median , very low , continuous with the caudal ; caudal moderately broad , and round with ray - like markings ; ventral finfold very low , origin somewhat posterior to last gill aperture , extending to anus ( ref . 6885 ) . prune colored , preserved specimens black ; frequently piebald with light spots ; the very edges of caudal and ventral finfolds may be light colored ( ref . 6885 ) .
the hagfish is famous for its ability to emit mucus and even its scientific name is derived from the greek word for slime . one single hagfish can fill a milk jug with slime in no time . the slime is probably a way for the hagfish to fend of predators , since the slime can be used to form a protective slime - cocoon . if a fish tries to eat the cocoon , the slime can clog its gills and make it suffocate . if you try to chew hagfish slime , it will expand .
after the shark encounter , we looked for a good place to deploy the baited benthic traps we were carrying . the mussel beds around the brine pool are covered with hagfish , so we placed the traps on its periphery , in hopes of trapping fewer hagfish and perhaps a crab or two . remarkably , hagfish were even swimming in the brine pool , which is four times saltier than seawater . on other expeditions , scientists have taken pictures of dead fish floating up in the brine ; hagfish must have a remarkable salt tolerance .
hagfish may be one of the most abundant groups of demersal fishes in many areas , in terms of numbers and / or biomass .
cailliet , g . m . , mcnulty , m . and lewis , l . ( 1991 ) habitat analysis of pacific hagfish (
lesser , m . , martini , f . h . and heiser , j . b . ( 1996 ) ecology of hagfish ,
pacific hagfish - eptatretus stoutii the pacific hagfish is found on muddy bottoms in cold ocean waters along the pacific coast from vancouver , canada south to baja california , mexico . source : animal diversity web intended audience : general reading level : middle school teacher section : yes
the atlantic hagfish or “slime eel” , myxine glutinosa , is found in deep , cold waters to depths of at least 1100 m . in the western north atlantic , hagfish are distributed from davis straits , greenland to the continental slope waters off of florida . in the gulf of maine the distribution of hagfish is primarily affected by salinity , temperature and substrate type ( collette and klein - macphee 2002 ) .
hagfish is considered to be the most primitive vertebrate species either living or extinct ( collette and klein - macphee 2002 , powell et al 2005 ) . hagfish evolved over at least 300 million years and have the same basic morphological traits of fossilized specimens ( bardack 1991 ) .
ronan , m . ( 1988 ) the sensory trigeminal tract of the pacific hagfish : primary afferent projections and neurons of the tract nucleus .
, n . sp . , a new hagfish ( family eptatretidae ) from south australia , with a key to the 5–7 gilled eptatretidae .
the hagfish is a true monster of the deep . to see why , one only has to examine its greusome feeding habits . a hagfish begins its feeding process by attaching itself to a passing fish . once firmly attached , it then bores its way inside its unsuspecting host . once inside , the hagfish will actually eat the fish ' s flesh with a specialized rasping tongue . it literally eats its victim from the inside out . when no large prey can be found , hagfish will feed on worms and other small invertebrates they find on the ocean floor . hagfish have a very slow metabolism and can go for months without feeding . they can sometimes be a nuisance to fishermen because they can spoil an entire catch of deep sea fish before the catch can be hauled to the surface . one catch of fish can contain hundreds of hagfish .
6 . a 2011 report from the international union for conservation of nature ( iucn ) found that 12 % of hagfish species are at an elevated risk of extinction . one hagfish species is critically endangered , two are endangered , six are vulnerable to extinction and two are near - threatened .
these fish are affected by the trash and chemicals that we put into the ocean . pacific hagfish are a crucial part of the cycle of life as they eliminate dead and dying organisms . there could be a significant impact on the ecosystem should there be a large scale removal of hagfish .
the seal shark dalatias licha ( a–c ) and the wreckfish polyprion americanus ( d–f ) fare poorly when they attack the hagfish . ( image :
as late as 2006 , a new member was added to the hagfish family myxinidae when the goliath hagfish was scientifically described by mincarone & stewart and given the name eptatretus goliath . eptatretus goliath was described from a specimen caught at a dept of 811 metres ( 2 , 661 feet ) at the head of the hauraki canyon off the northeast north island in new zealand . the species was named goliath since it was a true giant in the world of hagfish ; the specimen measured an astonishing 127 , 5 cm ( approximately 50 inches ) . this makes eptatretus goliath the largest known species of hagfish .
reference : zintzen , roberts , anderson , stewart , struthers & harvey . 2011 . hagfish predatory behaviour and slime defence mechanism . scientific reports . urltoken
horn - like teeth . atlantic hagfish belong to the family myxinidae which have one pair of gill openings attached to 6 - 7 internal gill pouches per opening . the species has paired barbels on the tip of its snout and four barbels surrounding the mouth . hagfish are almost blind because their eyes are rudimentary but their sense of smell is keen . the skin of the atlantic hagfish is smooth and scale - less with a series of slime glands along both sides of the ventral midline ( collette and klein - macphee 2002 ) . these glands produce fibrous mucus that protects hagfish from predators and possibly parasites .
the humble hagfish produces a sticky slime to defend itself from predators , as well as to hunt for its own food . now a team of swiss scientists has figured out the physics behind how the hagfish can use the same slimy substance for both purposes , according to a new paper in scientific reports .
“oregon had a limit on permits for a while , but now it’s an open - access fishery , ” he said , noting that “no one knows the science” of hagfish . while the slimy eels seem plentiful for the moment , he doesn’t want to see a repeat of korea’s depletion of homegrown hagfish .
martini , f . h . , heiser , j . b . and lesser , m . p . ( 1997 ) a population profile for hagfish ,
the mouth of the hagfish is perfectly adapted to tearing flesh away from dead and dying animals and is also great when it comes to catching marine invertebrates such as bristleworms . inside the mouth you will find a single tooth and a tongue equipped with pairs of rasps . every time the hagfish pulls back its tongue into the mouth , the rasps will pinch together . the hagfish attach its mouth to a fish or other animal and gradually work its way through the animal .
bottom dwellers , pacific hagfish are typically inhabits temporary burrows in mud and other soft substrate at depths of 18 - 900 m ( 584 - 2970 ft ) .
wicht , h . and northcutt , r . g . ( 1992 ) the forebrain of the pacific hagfish : a cladistic reconstruction of the ancestral craniate forebrain .
the atlantic hagfish is a deep - water fish . they can be found at depths of up to 5 , 600 feet ( about 1 , 800 meters ) . they are known on both sides of the north atlantic ocean as far north as norway . hagfish prefer soft sea bottoms where they can quickly bury themselves when threatened .
dr . frank holds a hagfish caught in one of the benthic traps . these fish appear to be prevalent at the brine pool . click image for larger view .
the hagfish has a fairly primitive look and since it was viewed as a form of parasite earlier , scientists suggested that its primitiveness was caused by this parasitic lifestyle . today , most scientists instead think that the hagfish is so perfectly adapted to its environment that no changes have been necessary during the most recent several hundred million years .
bardack , d . 1991 . first fossil hagfish ( myxinoidea ) : a record from the pennsylvanian of illinois . science , vol . 254 : 701 - 703 .
falkmer , s . , marklund , s . , mathisson , p . and rappe , c . ( 1977 ) hepatomas and other neoplasms in the atlantic hagfish (
hagfish are well known for their ability to tie themselves in knots , which can travel down the length of their bodies . this could help to clear their own bodies of slime ( they can choke on their own mucus ) or free themselves from the grip of a predator . here , the knot seemed to give the hagfish leverage for pulling the bandfish from its burrow . zintzen thinks that the hagfish may even have used its mucus as an offensive weapon , to choke the bandfish inside its burrow .
reporting of atlantic hagfish landings is presently not required by law and fishery data are therefore incomplete . atlantic hagfish landings first appear in the nefsc commercial database in 1993 with a reported landing of approximately 500 metric tons . annual reported landings during 1994 - 2000 ranged between 1 , 100 and 3 , 000 metric tons with a peak in 2000
crewmembers from the f / v first hope unload hagfish – otherwise known as slime eels – at the port dock in newport , oregon . vessel owner frank button has plied the waters off the oregon coast for hagfish for the past three years . it’s a wide - open , year - round fishery with an eager market in korea .
as mentioned above , a hagfish will contain both ovaries and testes , but these fishes are functionally non - hermaphroditic . young fishes are hermaphroditic , but as they age they will become either male or female . the hagfish may however switch sex from season to season if it finds itself in a group where another sex would be more favourable .
zintzen filmed slender hagfish chasing after red bandfish , ensconced in sandy burrows . the hagfish completely ignored the bait that zintzen was offering . instead , they seemed to search the ocean floor for hidden burrows , using the whisker - like barbels on their faces . once they found an entrance , they rapidly burrowed inside , emerging several minutes later .
kabasawa , h . and ooka - souda , s . ( 1991 ) circadian rhythms of locomotory activity in the hagfish and the effect of the light - dark cycle .
ooka - souda , s . , kadota , t . and kabasawa , h . ( 1991 ) in the hagfish visual information sets the circadian pacemaker via the pretectum .
9 . to ward off predators and other fish trying to steal their meals , hagfish produce slime . when harassed , glands lining their bodies secrete stringy proteins that , upon contact with seawater , expand into the transparent , sticky substance . according to common hagfish mythology , they can fill a 5 - gallon bucket with the stuff in mere minutes .
matsuda , h . , goris , r . c . and kishida , r . ( 1991 ) afferent and efferent projections of the glossopharyngeal - vagal nerve in the hagfish .
january 13 , 2012—for the first time , scientists have recorded the defense strategy of the hagfish , which , when attacked , secretes slime from hundreds of pores on its body .
in the gulf of maine ( gom ) , atlantic hagfish are caught using modified 55 - gallon plastic barrels , called hagfish pots , attached to sinking line and buoys . typically 20 - 40 traps are deployed in a string for a small commercial vessel and 80 - 200 traps for larger vessels ( nefsc 2003 ) . a series of funneled holes in the side of the barrel allow hagfish to enter the baited pot but doesn’t allow them to escape . several rows of 3 / 8” holes allow smaller animals to escape the traps .
ferocious fangs aren’t the purpose this weird fish is included in our list , however . hagfish have an entirely revolting trick up their sleeves to avoid predators . when disturbed , the hagfish will ooze proteins from slime glands in its skin that interact with the surrounding water to form a thick , slimy outer coating which ultimately expands into a huge mass of slime . in fact , deep - sea diving equipment has been thwarted from reaching its final destination in the past by large amounts of hagfish slime , produced when the fish are alarmed .
7 . no one is sure whether hagfish belong to their own group of animals , filling the gap between invertebrates and vertebrates , or if they are more closely related to vertebrates .
zintzen also filmed some hagfish hunting , a behaviour that had been suspected but never witnessed . while they’re typically regarded as scavengers , some scientists have suggested that their numbers are so great that they couldn’t possibly be sustained by corpses alone . on top of that , some people have found the flesh of prawns , worms and fish among the stomach contents of hagfish .
walvig , f . ( 1967 ) experimental marking of hagfish ( myxine glutinosa l . ) . norwegian j . zool . ( nytt . mag . zool ) , 15 , 35–3
hagfish slime can be both . it turns out that the suction feeding employed by many of the hagfish’s predators creates a unidirectional flow . the elongated stress of that sucking flow increases the goo’s viscosity , the better to suffocate said predators by clogging of the gills . but when the hagfish is trying to escape from its own slime , its motion creates a shear - thinning flow that actually reduces the viscosity of the slime , making it easier to escape . in fact , the slimy network quickly collapses in the face of a shear - thinning flow .
considered a scavenger , the hagfish feeds mostly on dead and dying fish and marine mammals , thereby playing an important role in the ecosystem . using its keen sense of smell , the hagfish will identify its food source and either burrow into its prey by making a hole with its rasping teeth , or entering through an existing opening to consume it from the inside out , usually only leaving skin and bones when it is done . due to its slow metabolism , the hagfish may survive for up to seven months without eating . when other food sources are not available , it subsists on worms and other bottom fauna . the hagfish is preyed upon by some marine mammals and large invertebrates , but most stay away due to the risk of slime suffocation .
spitzer , r . h . , downing , s . w . and koch , e . a . ( 1979 ) metabolic - morphologic events in the integument of the pacific hagfish (
pacific hagfish are among the very first arrivals at a whale fall in deep waters off the california coast . called mobile scavengers , they feast on the soft tissue of the whale carcass / .
nishizawa , h . , kishida , r . , kadota , t . and goris , r . c . ( 1988 ) somatotopic organization of the primary sensory trigeminal neurons in the hagfish ,
pacific hagfish , like other hagfish , represent an ancient form of life that has remained virtually unchanged since the paleozoic era 450 million years ago . it is a cartilaginous fish that lacks scales , paired fins , a stomach , and true jaws . it has rudimentary eyes ( eye spots ) that are only able to detect light , and relies on its keen sense of smell and touch to get around ( using a single nostril and barbels , respectively ) . the hagfish ' s jawless mouth contains two parallel rows of pointed keratinous teeth , which are secured to rasping dental plates .
the hagfish looks like an easy meal . its sinuous , eel - like body has no obvious defences , but any predator that moves in for a bite is in for a nasty surprise . the hagfish releases a quick - setting slime that clogs up the predator’s gills , causing it to gag , choke and flee . scientists have known about this repulsive defence for decades , but vincent zintzen has finally filmed it in the wild . his videos also prove that hagfish , generally thought to be scavengers of the abyss , are also active hunters that can drag tiny fish from their burrows .
unique vertebrates , hagfish are able to absorb nutrients through their skin . they prefer polychaete worms for a meal but also prey on small invertebrates and are scavengers of dead and dying marine life . once a firm hold is established on the prey , the hagfish ties and untied a knot within its own body to create a ripping force . it then burrows into dead carcasses exposing its skin to the nutrient - rich decomposing matter while eating away at the dead animal’s inside . it leaves the skin and bones behind . due to their slow metabolism , hagfish can survive for several months without eating .
hagfish play an important role in the oceans ecosystem , getting rid of ( e . g . , eating ) decaying material on the sea floor . as a biological oceanographer , i ' m intrigued by the functions lifeforms perform in the deep . this does not mean , however , that i enjoy being up close and personal with hagfish , as my graduate student nicole mcmullen and i were last night .
“ friends of oceanography public lecture series explores the strange , wondrous , and disgusting hagfish ” , university of rhode island , 2002 - 03 - 25 . retrieved on 2008 - 03 - 28 . urltoken
11 . to prevent choking on its own slime , a hagfish can “sneeze” out its slime - filled nostril , and tie its body into a knot to keep the slime from dripping onto its face .
to retrieve the slime , they placed the hagfish in a bucket of cold seawater and used a mix of clove bud oil and ethanol to anesthetize them . then they put the hagfish on a dissection tray , blotted them dry , and zapped them with electricity to make the muscles contract and expel the milky pre - slime from the pores . finally , the fish were transferred to nice , comfy recovery bath .
davison , w . , baldwin , j . , davie , p . s . , forster , m . e . and satchell , g . h . ( 1990 ) exhausting exercise in the hagfish ,
the hagfish is almost completely blind , but it has a good sense of touch and smell . it has a ring of tentacles around its mouth that it uses to feel for food . it has a tongue - like projection that comes out of its jawless mouth . at the end of the projection are tooth - like rasps that close when the
tongue
is pulled back into the hagfish ' s mouth .
the hagfish is almost blind , but it has not problem detecting food since it is equipped with highly developed senses of touch and smell . no less than four pairs of sensing tentacles are located around its mouth .
we still know very little about how hagfish reproduce , but we do know that each fish contains both ovaries and testes and that the parents do not guard their offspring . one and a half century ago , the royal danish academy of sciences and letters ( kongelige danske videnskabernes selskab ) announced an award to anyone who could solve the mystery about how the hagfish reproduces . as of 2008 , no one has received the award .
the pacific hagfish ( eptatretus stoutii ) is eel - like , with 10 to 14 pores along its elongated body . it usually ranges in color from tan to brown or grey on the top and lighter on the bottom . it can be found at depths ranging from 60 to 3000 feet on mud substrate . sampling of california commercial fishery landings has shown that the average pacific hagfish measures between 12 and 18 inches in length .
8 . the only known fossil hagfish , from 300 million years ago , looks very much like a modern hagfish , leading some scientists to speculate that it has changed little since then . “it’s an indication , not that they’ve stalemated and are not evolving , but that they have arrived at a body plan that is still very successful today , ” says tom munroe , a fish zoologist at the smithsonian national museum of natural history .
the larval stage can last as long as seven years ! at the end of the larval state , the lamprey changes into an eel - like creature that swims and usually attaches itself to a fish . there are around 50 living species of lampreys . the hagfish is also know as the slime fish . it is eel - like and pinkish in color . it has glands along its sides that produce a thick , sticky slime that it uses as a defense mechanism . the hagfish can also twist its body into knots ! it may do this to clean off slime or escape predators . the hagfish may also sneeze to clear its nostrils of slime .
science now hagfish just got more disgusting urltoken proc . r . soc . b adaptations to in situ feeding : novel nutrient acquisition pathways in an ancient vertebrate http : / / rspb . royalsocietypublishing . or . . .
it seems to be working because most fishes don’t only bite : they open their mouth quicky to suck water and prey into their mouth before biting . in the case of hagfish , they suck the slime as well .
it ' s an interesting and novel result ,
says fish ecologist jeffrey drazen of the university of hawaii , manoa . when it ' s not busy consuming cadavers , the hagfish ' s larger role in the food web remains a mystery , he says , as it ' s difficult to study fish that live this deep in the ocean . the new finding is the latest in a list of hagfish feeding habits that would make miss manners weep . for instance , hagfish coat a corpse they ' re interested in with slime exuded from pores in their bodies , keeping other scavengers at bay .
nobody else wants it after that ,
drazen says .
research is being done on hagfish slime in which the mechanical properties of threads made from the slimy mucus are being studied . the threads are both strong and stretchy , features that may lead to development of superior new materials .
starting off our list of weird animals with absolutely disgusting defense strategies is the particularly handsome hagfish ( eptatretus stoutii ) . these jawless , spineless denizens of the deep are a throwback to the paleozoic era when fish evolved . using feelers located on the ends of its face , the hagfish locates dead and rotting animals that have sunk to the bottom of the ocean floor . swarms of hagfish will penetrate the decomposing carcass and feast on the body from the inside out . it uses its razor sharp teeth to bite and tear rotting flesh right off the bones . it’s a good thing the poor animal is dead when all of this is happening because good god that sounds painful .
since the hagfish feed on carcases , it might be able to worn us about cancerogenous compounds in the environment . it is a well known fact that many dangerous pollutants congregates along the food chain , and a scavenger like the hagfish will therefore ingest large amounts of pollutants . today , primary liver cancer is rare in humans living in western europe , but fairly common in africa and china where the environmental laws tend to be less strict or poorly enforced .
12 . although their eating habits seem disgusting , hagfish help clean and recycle dead animals from the seafloor . they also serve as a food source for fish , seabirds and seals—at least those that can make it through the slime .
in areas where there is considerable bycatch discarded by fishermen , or falls of marine mammals such as whales and sea lions , hagfish may play a significant role in recycling and maintaining the seafloor by savaging and burrowing through the substrate .
agnatha are jawless fish . lampreys and hagfish are in this class . members of the agnatha class are probably the earliest vertebrates . scientists have found fossils of agnathan species from the late cambrian period that occurred 500 million years ago .
in the early 1990s , the exported hagfish were used primarily for eel - skin leather , not food . as demand for eel - skin leather dropped , so did west coast exports . by 2000 , overfishing had depleted korea’s hagfish stocks , so buyers looked elsewhere , including the west coast . processors learned that korean buyers rarely purchased west coast hagfish because they didn’t like the method oregon processors used to freeze the eels . that changed in 2002 , when mike erdman of oregon sea green products in coos bay / north bend decided to do something about it , traveling to korea to learn their freezing techniques and in the process creating a niche for oregon , washington and to some extent california .
although hagfish was a traditional food item in japan and korea , harvesting of the fish for their skin to be used as soft leather did not start until world war ii brought about a shortage in japan for leather from land animals .
after the catch , fishermen and processors stay busy removing slime from hagfish tanks to keep them alive . for shipping , processors pack the eels into containers filled with saltwater and liquid oxygen to keep them breathing and keep the containers cool .
there are a few reasons why the slime might be useful in the fashion world : it’s incredibly strong , easily stretched , and when it dries , the texture becomes silky . while a hagfish only reaches up to a foot in length , one animal alone contains hundreds of miles of slime . that’s why researchers are trying to replicate the proteins of hagfish slime as we speak , in order to be able to manufacture an artificial product with similar properties . ( source )
this is the first time such feeding habits have been observed in a non - invertebrate animal , suggesting that hagfish may be a transitional organism between modern fish and invertebrates such as aquatic worms , which can absorb food through their skin .
the hagfishes are believed to have been around for at least 500 million years without changing much and are therefore of great interest for scientists that wish to understand more about how different life forms have evolved on our planet . the hagfish is for instance equipped with an anatomical feature that is believed to be the beginning of a vertebral column . the hagfish has no cerebrum or cerebellum , no jaws and no stomach , and its skeleton is made up by cartilage instead of bones .
we placed the traps in two different locations , then motored back to pick up the eits camera . on the way , i saw several hagfish swimming happily toward my traps . sigh . the glamorous life of a marine biologist . . .
powell , m . l . , s . i . kavanaugh and s . a . sower . 2005 . current knowledge of hagfish reproduction : implications for fisheries management . integrative and comparative biology 45 ( 1 ) : 158 - 165 .
shelton , r . g . j . 1978 . on the feeding of hagfish myxine glutinosa in the north sea . j . mar . biol . assoc . u . k . , vol . 58 , pp . 81 - 86 .
nicole and i carried the traps to the light - tight cold room , where we excitedly opened them under dim red light . instead of seeing beautiful shrimp and crabs with glowing eyes , we saw blind hagfish heads poking up at us from the traps .
hagfish slime is strong and hard to remove , because unlike the other known forms of slime found in nature hagfish slime is reinforced with special fibres . inside the slime , each fibre is no thicker than a thousandth of a millimetre , but the fibres are very strong and can reach a length of half a metre ( 1 foot 8 inches ) . we still do not know how the fibres are put together , but scientists are trying to find out since that knowledge might make it possible to create really strong synthetic materials .
probably eating their way out of the carcass , according to a new study—and not with any sort of politesse , either . when they can ' t pack enough flesh into their tentacle - lined mouths , hagfish absorb the carcass ' s nutrients right through their skin .
atlantic hagfish inhabit soft clay or muddy sediments and spend much of their time in temporary burrows in the sea floor ( collette and klein - macphee 2002 ) . they prey primarily on shrimp , worms and small crabs ( gustafson 1935 , shelton 1978 , collette and klein - macphee 2002 ) . they are also scavengers that feed upon dead and dying fish , mammals and shellfish . hagfish are often considered a nuisance by commercial fishermen because they can feed on targeted species ( martini et al 1997 , collette and klein - macphee 2002 ) .
grant , s . m . 2006 . an exploratory fishing survey and biological resource assessment of atlantic hagfish ( myxine glutinosa ) occurring on the southwest slpoe of the newfoundland grand bank . j . northw . atl . fish . sci . , v 36 : 91 - 110 .
martini , f . m . lesser and j . b . heiser . 1997 . a population profile for atlantic hagfish , myxine glutinosa ( l . ) , in the gulf of maine . part i : morphometrics and reproductive state . fishery bulletin 95 : 311 - 320 .
wells , r . m . g . , forster , m . e . , davison , w . , taylor , h . h . , davie , p . s . and satchell , g . h . ( 1986 ) blood oxygen transport in the free - swimming hagfish ,
the most distinguishing hagfish behavior is its ability to produce copious amounts of mucilaginous slime nearly instantaneously . pores along the degenerate lateral line secrete the slime as a defense mechanism . as the slime contacts seawater , it rapidly expands into a sticky gel that can suffocate an attacker or foul mechanical equipment . another unique a hagfish behavior is its ability to tie a knot in its body and then slide in and out of the knot . they can use this behavior to bury into a carcass to elude predators , gain leverage to tear off pieces of flesh , or clean slime from itself .
the hagfish has for instance been used by researchers studying the islets of langerhans , a special type of pancreatic cells responsible for producing insulin . hagfishes are of special interest since their insulin is the most primitive form of insulin known to science . in hagfish , insulin is produced in a small organ named the islet organ which is located on the bile duct wall at the section where the bile duct opens into the bowels . by learning more about this primitive form of insulin , researchers hope to understand more about how the insulin production works in the human body and why it sometimes malfunctions .
“when i first reviewed this video , i thought : those hagfish are not very clever . they have the bait right above their head and they keep on searching the sediment for it . ” then , zintzen noticed one particular hagfish that had stuck the front third of its body inside a hole . it twisted its body into a knot , using it for leverage to push against the sediment . twenty seconds later , it withdrew from the burrow with a red bandfish , dead and motionless , in its mouth . “i then only understood what was actually happening : they were hunting ! ”
hagfish , the eel - like , slime - emitting wrigglers of the sea floor , just can ' t get enough of decaying corpses . when they come across a dead fish , they snuggle their sinewy bodies down into its cavities and stay there , writhing blissfully . but what are they doing ?
the ability of a hagfish to tie itself into a knot and then untie is believed have several purposes . it may pull its body through the knot so as to remove itself from its own slime that would otherwise suffocate it or the knot can be used as leverage for tearing meat from a carcass .
the salt concentration of a hagfish ' s tissue is the same as that of the seawater it normally swims in , suggesting that dissolved substances can cross the skin . to determine whether the animals can soak up nutrients as well as salt , physiologist chris glover of the university of canterbury in christchurch , new zealand , and colleagues took a piece of hagfish skin and stretched it out in a flask containing a seawater - like solution on one side and a solution resembling a hagfish ' s own bodily fluids on the other . in the seawater , they dissolved radioactive amino acids and sugars , along with food coloring to test how permeable the skin was . after a few hours , the skin started to become radioactive as it absorbed the amino acids , the researchers reveal online this week in the proceedings of the royal society b . the skin didn ' t allow food coloring through , however , suggesting that it selects nutritious detritus .
there have been prior studies on the unusual fluid properties of hagfish slime . but lead author lukas boni of eth zurich in switzerland and his colleagues wanted to focus specifically on how those properties played a role in the animal’s defense system—as well as its trick of tying itself in knots to escape from its own slime .
fernholm , b . , 1998 . hagfish systematics . p . 33 - 44 . in j . m . jørgensen , j . p . lomholt , r . e . weber and h . malte ( eds . ) the biology of hagfishes . chapman & hall , london . 578 p . ( ref . 31276 )
5 . although they are jawless , hagfish have two rows of tooth - like structures made of keratin that they use to burrow deep into carcasses . they can also bite off chunks of food . while eating carrion or live prey , they tie their tails into knots to generate torque and increase the force of their bites .
but the more promising applications are far less frivolous . it could be used to staunch bleeding in accident victims during surgery , for instance , expanding upon contact with the salty blood . the stretchiness—akin to the plastic rings that hold together six packs of beer—would make hagfish slime useful in biomedical devices , tissue engineering , or biosensors .
you can see the results below . the hagfish in the videos are attacked by sharks , conger eels , wreckfishes and more . in less than half a second , the predator’s mouth and gills are filled with slime . it leaves , gagging and convulsing , slime hanging in long wisps from its head . even voracious seal sharks turn tail . the cameras didn’t follow the fleeing predators , so zintzen doesn’t know if they eventually died or if the slime dissolved away . either way , the hagfish , uninjured and oblivious , just carried on feeding . its defence is so effective that it can totally ignore the fact that a shark just tried to bite it .


synodontis is the largest genus of mochokid catfishes .

it is the biggest genus within the 10 genera and 190 different species in the mochokidae family .

synodontis has over 131 different species within the genera .

synodontis are also known as squeakers , due to their ability to make stridulatory sounds through their pectoral fin spines when handled or disturbed .

synodontis make a sound that sounds like squeaking by rubbing their spines together .

they do this when they have been frightened or when they become angry .

" synodontis " may also squeak when they are taken out of the water .

these catfish are small - to medium-sized fish with many species exhibiting attractive spotted markings .

some species are also known for naturally swimming belly-up , earning the name upside-down catfish .

some of these species are synodontis contractus and synodontis nigriventris .

while some of these species are known to swim upside down , another species , synodontis multipunctatus , is a brood parasitic cuckoo catfish .

synodontis

lateral view of synodontis ornatipinnis , illustrating the striking patterns seen in some species of synodontis ; cu 91403 . ©
synodontis schall surface shore bottom habitats araoye , p . a . spatio - temporal distribution of the fish synodontis schall ( teleostei : mochokidae ) in asa lake , ilorin , nigeria
synodontis ocellifer was , at one time , a fairly rare fish in the hobby . what was once a fish shipped accidentally with other synodontis is now imported separately in fairly decent numbers .
spine anatomy reveals the diversity of catfish through time : a case study of synodontis ( siluriformes ) .
synodontis schoutedeni is known from pool malebo ( stanley pool ) and from the central congo river basin .
a synonym of brachysynodontis barensoda ( rüppel , 1932 ) . see the species synodontis batensoda rüppel , 1932 .
i think i may be experiencing auditory hallucinations . i am convinced i have heard my synodontis squeaking at me .
synodontis schall is able to adapt to many different kinds of food and habitats , increasing the chances of survival .
synodontis soloni is a benthopelagic species . it is oviparous with distinct pairing during breeding ( breder and rosen 1966 ) .
synodontis pleurops is a benthopelagic species . it is oviparous with distinct pairing during breeding ( breder and rosen 1966 ) .
spine anatomy reveals the diversity of catfish through time : a case study of synodontis ( siluriformes ) . - pubmed - ncbi
bi tree of synodontis catfish . voucher and field numbers ( see the electronic supplementary material ) are used to distinguish multiple specimens . lm , lake malawi ; lv , lake victoria ; rm , river malagrasi ; sa , south africa . photographs top to bottom : s . nigromaculatus , s . njassae , s . granulosus , s . multipunctatus , s . victoriae , synodontis cf . tanganaicae , s . af . petricola , synodontis dhonti , synodontis polli and s . cf . petricola .
if you really want to know , this article from planet catfish is an excellent in depth guide to identifying hybrid synodontis .
synodontis species vary greatly in adult size , from 5 cm total length ( tl ) in the recently described s . acanthoperca ( friel & vigliotta , 2006 ) up to 80 cm in other species . larger synodontis are important food fishes in many parts of africa . species in other mochokid genera are even smaller as adults ( e . g . , microsynodontis and chiloglanis ) , but none are larger than the largest synodontis . synodontis angelicus may reach about 25 cm tl ( poll , 1971 ) .
whether you care if your synodontis is a hybrid or not will depend on whether you intend to attempt breeding ( a very noble goal indeed , given the difficulty of breeding synodontis , ) or whether you are paying a premium for a ' pure ' fish .
if you are keeping several synodontis in the same tank , ensure that you provide plenty of hiding places and have a spacious aquarium .
also look out for synodontis sp . ' golden eye ' , which is a bit like synodontis multipunctatus . it ' s being bred in the uk and some specialist stores are stocking the very attractive juveniles . look out in this mag next month for more details .
a large - scale phylogeny of synodontis ( mochokidae , siluriformes ) reveals the influence of geological events on continental diversity during the cenozoic .
froese , rainer and pauly , daniel , eds . ( 2011 ) .
synodontis schall
in fishbase . december 2011 version .
there are many species of synodontis , and there are many hybrids and crossbreeds between the species which pop up as well , quite often in pet shops . synodontis appear to be quite happily and readily crossbred to the chagrin of purists who do not approve of such abominations .
musschoot , t . , and p . lalèyè . 2008 . designation of a neotype for synodontis schall ( bloch and schneider , 1801 ) and description of two new species of synodontis ( siluriformes : mochokidae ) . journal of natural history 42 ( 17 - 18 ) : 13031331 .
fossil mochokids ( almost exclusively synodontis ) are widespread in africa and date as far back as the early miocene ( stewart , 2001 ) . interestingly , fragments of synodontis pectoral spines dating from the early oligocene have been found in oman , an area where mochokids do not exist today .
synodontis : from the greek syn , meaning together , and odontos , meaning tooth ; in reference to the closely - spaced lower jaw teeth .
evaluation of the fossil fish - specific diversity in a chadian continental assemblage : exploration of morphological continuous variation in synodontis ( ostariophysi , siluriformes ) .
fossil mochokids , of the genus synodontis , have been found in deposits from eastern and northern africa dating to at least the early miocene ( at least 20 mya ) ( stewart , 2001 ) . interestingly , fragments of pectoral spines of synodontis dating from the early oligocene have been found in oman , an area where mochokids do not exist today ( otero & gayet , 2001 ) . fossil mochokids outside of the genus synodontis are presently unknown .
the true upside - down catfish , synodontis nigriventris , is adapted for feeding from the surface on insects and other items that fall into the water .
synodontis multipunctatus is native to lake tanganyika and therefore also a suitable inhabitant for rift lake cichlid fish aquariums . s . multipunctatus is one of the most popular of the synodontis catfishes . this popularity started with those aquarists who kept cichlids from lakes tanganyika and malawi and has spread widely from that base .
synodontis is a genus of upside - down catfishes . they are members of the african catfish family mochokidae which contains about 150 different species in 10 genera .
favours fast - flowing rocky habitats and is the only synodontis species found in rapids , where it lives in crevices ( tweddle et al . 2004 ) .
synodontis pleurops is known from the lower congo , pool malebo ( stanley pool ) and the congo river basin , with exception of the luapula - mweru system .
6a . eyes with free orbital margin ; 17 principal caudal - fin rays ( only 13 in synodontis contracta ) ; tail forked ; 6 to 10 pectoral - fin rays ( usually 8 or 9 ) ; lateral mandibular barbels with single , gracile branches at each point along length or doubly branched ( fig . 27a–b ) … synodontis
don ' t worry . synodontis do sometimes make noises that are audible outside the aquarium . this has earned them the name ' squeakers ' in parts of africa .
a large - scale phylogeny of synodontis ( mochokidae , siluriformes ) reveals the influence of geological events on continental diversity during the cen . . . - pubmed - ncbi
to cite this page : mr . thomas vigliotta , 2006 ,
synodontis angelicus
( on - line ) , digital morphology . accessed july 9 , 2018 at urltoken
synodontis schall has a shield on its body and has strong bony spines on the pectoral and dorsal fins . some areas of new evolutionary forces have allowed for the synodontis schall to have different phenotypes . recent studies have found evidence for an increase number of teeth and gill rakers which could possibly point to a change from them being herbivores to carnivores .
one in particular — a small , “common” synodontis — can be considered the standard bearer for the genus . the upside - down catfish ( synodontis nigriventris ) is without doubt the most popular and widespread ( in aquariums ) of the synodontis catfishes . this popularity is certainly not as a result of its color . the base color is generally brown , with small darker spots scattered on the body and head . two broad bands of lighter color may be seen on the body to the front and rear of the adipose fin .
day , j . j . , and m . wilkinson . 2006 . on the origin of the synodontis catfish species flock from lake tanganyika . biology letters 2 : 548552 .
. . . the consumption of fish scales by synodontis species has been observed by several authors ( e . g . lauzanne , 1988 ; ofori - danson , 1992 ) . however , whether or not the synodontis , especially s . koensis actively searches for scales or ingest them at random is a question that remains to be investigated . . . .
a much deeper - bodied synodontis , the synodontis eruptus is also known as the featherfin squeaker because off its beautiful feathered dorsal fin and the fact that it can produce a high pitched squeaking with it . these fish grow up to 20 centimeters , though 15 to 17 is more common , and have been reported as being more aggressive than other catfish .
for the concatenated data set , a total of 7 partitions were identified using partitionfinder ( table 1 ) . based on the concatenated data set and individual gene trees , the genus synodontis is monophyletic ( fig . 1 ; supplementary fig . s1a–d , doi : 10 . 5061 / dryad . b6225 ) . synodontis forms a clade with its successive sister taxa microsynodontis , mochokus , and mochokiella , which itself is sister to a clade , including chiloglanis , atopochilus , and euchilichthys . brachysynodontis batensoda and hemisynodontis membranaceus , 2 previously monotypic genera ( poll 1971 ) , nest within synodontis supporting morphological data ( vigliotta 2008 ) . based on our results and previous morphological findings , we therefore place these genera in the synonymy of synodontis .
bishai h . m . and y . b . abu gideiri . 1968 . studies on the biology of genus synodontis at khartoum . iii . reproduction . hydrobiologia 31 : 193202 .
sanyanga , r . a . 1998 . food composition and selectivity of synodontis zambezensis ( pisces : mochokidae ) in lake kariba , and the ecological implications . hydrobiologia 361 : 8999 .
gastrointestinal helminth parasites of the fish synodontis clarias ( siluriformes : mochokidae ) from lekki lagoon , lagos , nigeria por : akinsanya , bamidele , et al . publicado : ( 2007 )
there is also evidence of other recent dispersal events between the biogeographic clades . this is apparent within the ea clade , with dispersal into the cb ( 95 % hpd : 0 . 8–2 . 9 ma ) as the distinctive congolese taxon synodontis acanthomias is sister to the southern african synodontis nigromaculatus . in the reverse direction , the ea taxon synodontis afrofischeri ( lakes victoria / albert ) nests within the cb clade ( 95 % hpd : 4 . 0–8 . 6 ma ) . the single taxon ( synodontis aff . laessoei ) described from the cuanza ( angola ) ichthyo - province is also identified as having originated within the cb , but diverged much earlier from its congolese ancestor 11 . 9–21 . 3 ( 95 % hpd ) ma .
lalèyè , p . , chikou , a . , gnohossou , p . , vandewalle , p . , philippart , j c . & teugels , g .
studies on the biology of two species of catfish synodontis schall and synodontis nigrita ( ostariophysi : mochokidae ) from the ouémé river , bénin
. belgian journal of zoology 136 ( 2 ) : 193–201 .
synodontis generally mix well with other fishes and are easy to keep . larger ones could eat very small fishes , and they are often quite territorial towards other catfishes , especially other synos .
bishai h . m . and y . b . abu gideiri . 1965a . studies on the biology of genus synodontis at khartoum . i . age and growth . hydrobiologia 26 : 8597 .
sanyanga , r . a . 1998 . food composition and selectivity of synodontis zambezensis ( pisces : mochokidae ) in lake kariba , and the ecological implications . hydrobiologia 361 : 89 - 99 .
they are also known as the cuckoo synodontis as they have a habit of eating the eggs of other fish and depositing their own in place for the other fish to tend as they grow .
bishai h . m . and y . b . abu gideiri . 1965b . studies on the biology of genus synodontis at khartoum . ii . food and feeding habits . hydrobiologia 26 : 98113 .
if you are trying to identify whether or not a synodontis is pure , pay special attention to fin shape , size and coloration , to the nature of the barbs around the mouth , to the overall body shape of the fish and to its markings . if your synodontis seems to have the characteristics of more than one species , there is a fairly decent chance that it is a hybrid .
a peaceful synodontis species , these do not grow much over 12 centimeters . unlike other species of synodontis , these have been bred in captivity relatively easily , but prefer to live and spawn in groups , so a pair may not spawn alone . these are easily confused with multipunctatus , however they sport a white trim which is not present in the multipuncatus . they tend to be quite expensive .
the mochokid fossil record is represented largely by synodontis , predominately isolated robust fin spines ( pinton et al . 2006 ) . there are good diagnostic characters for fin spines of african catfish genera developed through extensive comparative material ( gayet and van neer 1990 ; pinton et al . 2006 ) , although extant synodontis are currently defined by 2 synapomorphies based only on soft tissue characters ( see vigliotta 2008 ) .
poll , m . 1971 . révision des synodontis africains ( famille mochocidae ) . annales de musée royale de l ' afrique centrale ( ser . 8 ) , sciences zoologiques 191 : 1 - 497 .
synodontis decorus is one of the most magnificent of the synodontis species ! it is hard to find a more stunning sight than that of an adult s . decorus swimming in an aquarium with its long , black dorsal fin trailer flowing behind . when seeing this species at the smaller sizes they are usually imported at , they are quite attractive , but this is merely a hint of the beauty to come .
synodontis schoutedeni is a benthopelagic species . its electric organ is located dorsally and consists of modified striated muscle ( møller 1995 ) . it is oviparous with distinct pairing during breeding ( breder and rosen 1966 ) .
lt cichlids are both polyphyletic , implying independent colonizations of the lake , and paraphyletic , demonstrating that radiations within the lake have subsequently become a source for secondary seeding of rivers and younger lakes ( salzburger et al . 2002 ) . in contrast , platytelphusidae crabs ( marijnissen et al . 2006 ) and cleopatra gastropods ( west & michel 2000 ) are monophyletic , consistent with single origins and no dispersal out of tanganyika . a current phylogeny is lacking for east african synodontis and thus it is not known whether the lt species flock is a single radiation . molecular markers have undermined the traditional taxonomies of some other lt groups ( e . g . rüber et al . 1999 ) , but have not yet been applied to synodontis , so that the extent of phylogenetic diversity of the lt flock is unclear . here , mtdna data are used to test current species concepts and to infer a dated phylogeny for lacustrine and fluviatile species of primarily east african synodontis . the phylogeny is used to test alternative hypotheses of the evolutionary history of synodontis in east africa , and in particular , whether the lt synodontis constitute a single radiation . synodontis catfish provide a parallel system that can be compared to other lake faunas to test the extent to which there are common patterns and processes of diversification in lt .
bishai , h . m . and y . b . abu gideiri . 1965 . studies on the biology of the genus synodontis at khartoum . i . age and growth . hydrobiologia 26 : 85 - 97 .
wright , j . j . and l . m . page . 2006 . taxonomic revision of the lake tanganyikan synodontis ( siluriformes : mochokidae ) . the bulletin of the florida museum of natural history 46 : 99154 .
synodontis schall is a benthopelagic , potamodromous species . it is found both in deep , open water and in quite shallow water , but it is never close to the shore ( worthington , 1929 ) . this species is an omnivore and feeds on insect nymph , larvae , eggs and detritus ( willoughby 1974 ) . it also feeds on fish , bivalves in the sudd and snails in gezira irrigation canals . synodontis schall is oviparous with distinct pairing during breeding ( breder and rosen 1966 ) . breeding occurs during the flood season ( bailey 1994 ) in comparatively shallow and sheltered waters ( worthington and ricardo 1936 ) . synodontis schall is utilized for human consumption .
in another article , i presented a brief overview of some of the basic principles for maintaining synodontis catfishes in the aquarium . now i would like to introduce a few of the various species that are available to hobbyists .
the genus synodontis is by far the largest and most well known in the family , and dozens of species are available in the hobby , ranging in size from just a few cm to well over 30cm / 12
.
wright , j . j . and l . m . page . 2008 . a new species of synodontis ( siluriformes : mochokidae ) from tributaries of the kasai river in northern angola . copeia 2008 ( 2 ) : 294300 .
in the wild the synodontis live in lagoons and other slow - flowing waters , often forming good sized groups . they are fish of the twilight and darkness and spend much of the day hidden under submerged tree trunks or riverbanks .
synodontis nummifer is known from throughout the congo river basin . it has not been found in centre of the democratic republic of the congo and in the southern tributaries of the congo river . records from the lower congo require confirmation .
synodontis soloni is known from the pool malebo ( stanley pool ) rapids and from libenge . it is also widely distributed in the lower congo ( roberts and stewart 1976 ) and from the ubangui river at zongo ( gosse 1968 ) .
araoye , p . a . ( 2000 ) .
pectoral spine size in synodontis schall ( teleostei : mochokidae ) from asa lake , ilorin , nigeria
. revista de biología tropical 48 ( 2 - 3 ) : 509–10 .
synodontis eupterus is , to my mind , one of the most outstanding of the synodontis catfishes . although it is not especially notable for its coloration ( a base gray - yellow to gray violet with darker markings in the form of winding lines in the young and small spots in the adult ) , the finnage , especially the dorsal , is what catches the eye . this fish well deserves its common name : feather fin synodontis . the dorsal fin , even in many juveniles , shows a distinct feathering . as the fish grows , this is additionally accentuated by increased prolongations of the soft rays , along with the accompanying membrane . the dorsal spine also shows similar extension with the growth of the fish .
monsters , these synodontis can grow over two feet in length . not at all recommended unless you have a very , very large fish tank , even 100 gallons won ' t cut it with one of these fish when they reach maturity .
synodontis nummifer is a demersal species . it is oviparous with distinct pairing during breeding ( breder and rosen 1966 ) . stomach contents contained sand , mud , plant debris , herbs and insect larvae ( mainly chironomids ) ( matthes 1964 ) .
koblmüller , s . , c . sturmbauer , e . verheyen , a . meyer , and w . salzburger . 2006 . mitochondrial phylogeny and phylogeography of east african squeaker catfishes ( siluriformes : synodontis ) . bmc evolutionary biology 6 : 49 .
. . . gy of synodontis in lake kanji ( nigeria ) described s . schall as omnivorous feeding on insect nymph and larvae , fish eggs , and detritus . hickley and bailey ( 1987 ) studying s . schall in the sudd swamps of the river nile ( sudan ) have pointed out the importance of detritus , benthic algae , macrophytes , benthic crustaceans , insects and fish in its diets . ofori - danson ( 1992 ) working on the ecology of some synodontis species in kpong headpond ( ghana ) indicated the dominant food items of s . schall as detritus , insects , oligochaeta , nematoda and hirudinea . sanyanga ( 1998 ) studied the food composition and selectivity of synodontis zambezensis in lake kariba and reported molluscivorous feeding habits . the specie . . .
synodontis ( mochokidae , siluriformes ) is a freshwater catfish endemic to africa . the 118 extant species are present in almost all hydrographic basins . some species are restricted to a single stream , whereas others have a vast distribution . synodontis is known in the fossil record since the miocene , and its history depends on the connections among african basins through time . the identification of species in the fossil record is essential to reconstruct this historical pattern . catfish pectoral and dorsal spines are robust , they preserve well and they form most of the fossil remains for the genus synodontis . unfortunately , the criteria for the identification of extant synodontis species are not applicable to fossil specimens . here , we define 11 original morphological characters that permit to discriminate four extant species from the chad - chari hydrographic system . six of these characters are defined on pectoral spines and five on dorsal spines . we then show that these characters can be used successfully for identifying fossil specimens . in particular , we present a case study in which we identify synodontis cf . schall and brachysynodontis cf . batensoda in the hominid - bearing sector toros - menalla ( late miocene , northern chad ) . we show that spine anatomy can be a powerful tool to recognise catfish species through time and thus to identify historical diversity pattern .
beyond diet , there isn’t a great deal known about the ecology of synodontis or other mochokids . synodontis stomach contents have included insects , nematodes , crustaceans , mollusks , annelids , seeds , algae , fish scales and incidentally sand ( bishai & abu gideiri , 1965 ; sanyanga , 1998 ; winemiller & winemiller , 1996 ) . the diets of the three sucker - mouthed genera ( see above ) may contain a higher proportion of plant matter , but it seems likely that all members of the family are omnivorous .
friel , j . p . , and j . p . sullivan . 2008 . synodontis woleuensis ( siluriformes : mochokidae ) , a new species of catfish from gabon and equatorial guinea , africa . proceedings of the academy of natural sciences of philadelphia 157 : 312 .
friel , j . p . and t . r . vigliotta . 2006 . synodontis acanthoperca , a new species from the ogôoué river system , gabon with comments on spiny ornamentation and sexual dimorphism in mochokid catfishes ( siluriformes : mochokidae ) . zootaxa 1125 : 4556 .
de weirdt , d . , e . vreven , and y . fermon . 2008 . synodontis ngouniensis , a new species ( siluriformes : mochikidae ) from ngounié and nyanga basins , gabon and republic of congo . ichthyological exploration of freshwaters 19 ( 2 ) : 121128 .
most fish have a cryptic colour pattern called countershading and their backs are darker than their bellies , making them more difficult for predators to see . but because synodontis swim the wrong way up , they use reverse - countershading so that their bellies are darker than their backs .
bayesian phylogenetic hypothesis of synodontis catfish reconstructed from the concatenated data set . outgroups ( gray branches ) , bpps are given in full below nodes , bs values are given above nodes : black square > 95 % , gray square 94–90 % , and gray star 89–85 % .
abu - gideiri , y . b . & nasr , d . h . ( december 1973 ) .
sound production by synodontis schall ( bloch - schneider )
. hydrobiologia 43 ( 3 - 4 ) : 415–428 . doi : 10 . 1007 / bf00015360 .
friel , j . p . and t . r . vigliotta . 2006 . synodontis acanthoperca , a new species from the ogôoué river system , gabon with comments on spiny ornamentation and sexual dimorphism in mochokid catfishes ( siluriformes : mochokidae ) . zootaxa 1125 : 45 - 56 .
synodontis is by far the largest genus in the family mochokidae and , indeed , one of the largest among all catfishes ( about 120 species , a close second to corydoras , about 150 species ) . and so , synodontis is often the stand - in when people think about mochokid catfishes . but , in fact , the family ( 10 genera , ~ 190 species ) is much more morphologically diverse when you consider some of the other recognized genera . euchilichthys , atopochilus and chiloglanis are particularly notable for their ventrally - directed sucker - shaped mouths . others like mochokus and acanthocleithron are very poorly known , but exhibit unique morphologies of their own . synodontis angelicus , like many mochokids , is typified by branched mandibular barbels , well - developed nuchal plates , a large cleithral process and s - shaped mandibular teeth set in a deep cavity / cup of the dentary .
the earliest synodontis is 21 . 8–16 . 6 myr old ( burdigalian ) , but younger fossils cannot be reliably assigned to extant species ( pinton et al . 2006 ) . molecular divergence time estimates were calculated using a pruned tree ( eliminating intraspecific data ) , assuming either 21 . 8 or 16 . 6 myr as the age of synodontis , and using the optimal smoothing parameter value , determined through cross - validation in penalized likelihood as implemented in r8s ( sanderson 2003 ) . confidence limits on age estimates were based on two mcmc chains sampling 500 generations and enforcing topological constraint .
nine genera and approximately 200 valid species are currently recognized . some fossilized pectoral spines have been attributed to synodontis , but none of them are described as new . phylogenetic relationships among the mochokid genera were investigated by vigliotta ( 2008 ) who found that chiloglanis is possibly a paraphyletic assemblage , that synodontis must include s . membranaceous and s . batensoda ( formerly placed in hemisynodontis and brachysynodontis respectively ) and that the reciprocal monophyly of atopochilus and euchilichthys are questionable at best ; all remaining genera are recovered as valid and monophyletic . the general relationships between mochokid genera are illustrated in the phylogeny below .
lt radiations leading to secondary colonization of rivers are rare in lt cichlid tribes ( salzburger et al . 2002 ) . the occurrence of a non - endemic synodontis within the lt species flock might be similarly explained if the flock were monophyletic . the phylogeny does not support this , but it and the time - scale are consistent with s . victoriae having originated in this way . thus , synodontis may provide a second example of recolonization . it is tempting to suggest that the ability to recolonize rivers is correlated with mobility , and that synodontis are more similar to cichlids than to benthic invertebrates , for which there is no evidence of recolonization ( e . g . marijnissen et al . 2006 ) , in this respect . unfortunately , the placement of s . victoriae is not compelling . we cannot reject the alternative hypothesis that the lt endemics are a single monophyletic radiation , which has not seeded any other rivers or lakes . east–west african faunal divisions , consistent with continental - scale vicariance , are reported for many terrestrial ( e . g . matthee et al . 2004 ) , but few aquatic groups . synodontis phylogeny reveals an initial east–west split and subsequent dispersal between the regional faunas .
my synodontis was 2
long in 1986 ! no typo . . . 1986 ! i know because in 11 / ' 86 we took our appaloosa stallion to the world champ show 100 ' s of miles away , for a week . had so many fish i got an amateur to feed while i was gone but worried what syno would eat . never let an amateur feed pellets ! the fish lucked out as the amateur quit the job after 1 day ( went deer hunting ) . this synodontis is still going as of 10 / 6 / 2013 . . . 27 yrs later !
julia j . day , claire r . peart , katherine j . brown , john p . friel , roger bills , timo moritz ; continental diversification of an african catfish radiation ( mochokidae : synodontis ) , systematic biology , volume 62 , issue 3 , 1 may 2013 , pages 351–365 , urltoken
synodontis catfishes span the entire geographic range of mochokids ; they inhabit a large proportion of african freshwaters including most of sub - saharan africa and the nile river basin and can be found in large rivers , smaller fast - flowing streams and the massive african rift lakes . some species are known to swim in mid - water and some will shoal ; others are primarily benthic and relatively solitary . synodontis angelicus is distributed throughout the congo river drainage ( poll , 1971 ) . anecdotal reports tell of angel squeakers using holes in submerged logs for shelter ; this practice is probably more widespread in the family .
in african freshwater , curved teeth are typical of mochokid fish . within the family , this shape is observed in synodontis , microsynodontis , mochokus and chiloglanis members ( pinton , otero , pers . obs . ) . this kind of tooth is usually attributed to synodontis in the fossil record because living species of microsynodontis are very small and because chiloglanis is a genus that inhabits fast moving waters , whereas synodontis are large - bodied and widespread , living in a variety of habitats . however , the description of giant fossil fish in another minute mochokid genus in the late miocene of chad , i . e . , mochokus [ 32 ] , suggest that one should not rely on size features to assign fossil remains to a given genus , notably in the case of mochokids . finally , the identification of mochokids at dur at - talah based on a single minute tooth is rather fragile and needs further confirmation .
ltt plots for the original synodontis data set ( dark gray ) and including missing species added at random ( light gray ) , estimated from sampling 100 bayesian trees generated from the concatenated data set . the solid line indicates the expected number of lineages under a constant rate model of diversification with no extinction .
unless you have a very common species , it may be difficult to tell if what you have is a hybrid or not . there are currently well over 100 different identifies species of synodontis , and more than one syno has been misidentified as a hybrid when it was , in fact a new species .
synodontis notatus is not one of the most attractive of the synodontis , but because of its general availability it deserves note here . this species has a gray - brown body color , with the ventral region being white . on the sides there are varying numbers of round , black spots along the midline . there may be as few as one spot per side — usually there are less than five — but on occasion there are more . the numbers of spots on each side of the body do not necessarily match . very rarely , an individual without spots on one side or the other may be seen .
a native of lake malawi , synodontis njassae is a pretty catfish with lovely coloration which can vary widely from fish to fish . some specimens may have many spots covering their body , others have but a few . some keepers break these into large and small spotted varieties . they grow to around 20 centimeters .
one species of synodontis is known for an interesting bit of its ecology ; s . multipunctatus is a brood parasite of mouth brooding cichlids such as haplochromis ( sato , 1986 ; wisenden , 1999 ) . adults of this species will ‘dump’ their own fertilized eggs into the mix while cichlids are breeding and the catfish eggs are taken into the mouth of a cichlid . the synodontis eggs hatch first and will eat the host eggs before they leave the host mouth . visit this link to see video of s . multipunctatus spawning with cichlids , and this link to see pictures of s . multipunctatus fry emerging from a cichlid mouth .
even more peculiar is the habit of some species of synodontis that are known to swim upside - down . this habit seems to be correlated with feeding while upside - down at the water’s surface ( bishai & abu gideiri , 1965b ) , but upside - down catfishes will rest and swim in the inverted position on a regular basis . chapman et al . ( 1994 ) showed that an upside - down posture near the surface also facilitates respiration in poorly oxygenated water . while the genus synodontis presents the most well - known species with their fascinating behaviors and natural histories , the family is actually much more interesting when taken as a whole .
the oldest reported fossil synodontis comes from the earliest lower oligocene , sultanate of oman at thaytiniti dated to 34 ma ( roger et al . 1993 ; otero and gayet 2001 ) and is represented by fin spines . these fossils possess a number of characters that in combination are used to diagnose synodontis from other african catfish ( gayet and van neer 1990 ) . these include : strong denticulation on the posterior border , round tubercles on the anterior border , a cleithral surface developed ventrally , a dorso - lateral process developed both anteriorly and laterally , and a well - developed auxiliary process ( gayet and van neer 1990 ; otero and gayet 2001 ) .
since the publication of the most recent taxonomic review of synodontis ( poll 1971 ) , a further 13 species have been described . the inclusion of multiple samples for species that have broad distributions within our study reveal reasonably distinct genetic divergences within taxa with large ranges , particularly across the n - s biogeographic region . k2p distances based on cyt b and coi range between 0 . 7 % and 2 . 1 % and may imply at least some cryptic speciation within the following taxa ( k2p distances for cyt b and coi given in parenthesis ) : synodontis sorex ( 2 % , 1 . 6 % ) , synodontis schall ( 2 % , 2 . 1 % ) , synodontis nigrita ( 1 . 6 % , 1 . 2 % ) , synodontis obesus ( 1 . 8 % , 1 % ) , synodontis clarias ( 1 % , 0 . 8 % ) , and the congo species synodontis angelica ( 1 . 2 % , 0 . 7 % ) . although not all these distances are > 2 % , often indicative of distinct species ( see april et al . 2011 ) , they are much greater than mean within species divergence ( 0 . 39 % based on coi ) reported in various marine fish species , for example ( ward et al . 2005 ) . the minimum timing of divergences within those taxa whose distances are < 2 % is 0 . 7–5 ma based on our multi gene data set . this pliocene–pleistocene timeframe was when the subtropical african climate periodically fluctuated between distinctly wetter and drier conditions , with evidence for increases in aridity at 2 . 8 , 1 . 7 , and 1 . 0 ma ( demenocal 2004 ) . these oscillations would have led to expansion and contractions of waterways potentially leading to isolation of populations . however , more extensive sampling of populations is needed to fully test the hypothesis for cryptic speciation in these taxa . additional new species from the cb that are highly cryptic in nature are also identified in this study ( fig . 1 , s . sp . nov . 2–4 ) . as such , our study highlights the need for further biodiversity surveys of african rivers , particularly the comparatively unexplored congo basin that will undoubtedly yield further species new to science and enhance the opportunity to test hypotheses of diversification scenarios .
synodontis schall was caught throughout the year , but highest catches were recorded in january and february , while total catch decreased from september to november when the lake became flooded as a result of increased water levels ( monthly mean range = 12 . 20 to 12 . 80 cm ) due to the rains that commenced in april (
all synodontis catfishes originate from africa . there are three areas of that continent where the majority of synodontis seen in the hobby come from : west africa ( mainly nigeria ) , zaire ( the “congo” ) and the rift lakes . i will discuss briefly , by geographical origin , some of the more than 100 species in this genus . although there is only space to deal with a small number of these fish , i hope you will have at least a better understanding about some of these fascinating catfishes . ( note : all sizes given are in total length [ tl ] , which is the full length of the fish including the tail fin . )
in the wild , this species is known to feed heavily on algae , so the addition of this or other vegetable fish foods to its diet is strongly recommended . with its small adult size and other similarities to s . nigriventris , this species offers good potential for someone wishing to try their hand at spawning a synodontis species .
lagrange recovered both dispersal and extinction rates of synodontis to be 0 . 003 per million years , respectively . figure 2 shows the most likely scenario of ancestral area reconstructions for nodes of interest summarized on the dated species - tree of the study group . three distinct biogeographical groupings are identified for synodontis based on the analysis combining wa regions . these comprise wa ( that includes the combined ichthyo - provinces : n - s , lgf , ugf ) ea and the cb , with wa rendered polyphyletic . in this scenario , the genus synodontis is inferred to have originated in the broad region of wa with subsequent dispersal within this region ( relative probability [ rp ] 0 . 99 ) . the picture is , however , less clear when these regions are coded separately , with the best likelihood reconstruction inferred for the origin of this genus as n - s with subsequent dispersal within this region , although this finding is equivocal ( likelihood scores were not significantly different between multiple reconstructions , rp 0 . 44 ) .
day , j . j . , peart , c . r . , brown , k . j . , friel , j . p . , bills , r . and moritz , t . 2013 . continental diversification of an african catfish radiation ( mochokidae : synodontis ) . syst biol 62 ( 3 ) : 351 - 365 .
the mochokidae are a family of catfishes ( order siluriformes ) that are known as the squeakers and upside - down catfish . there are 10 genera and about 188 species of mochokids here i will just deal with the most popular genera , the synodontis catfish . they are becoming more popular as availability increases , the synodontis are an interesting addition to any aquaria . their native ranges are the rivers and lakes of africa south of the sahara desert . all the family members are found only in africa . in the home they are most commonly seen in african cichlid tanks fulfilling the role of scavengers . to view some statistics on many individual fish , just click on any picture .
visual inspection of the ltt plot for synodontis indicates a near constant rate of diversification with no strong indication of a slowing down , irrespective of missing species added ( fig . 3 ) . net diversification rate for synodontis is 0 . 12 per ma assuming no extinction ( ϵ = 0 ) , decreasing to 0 . 07 per ma when assuming a high relative rate of extinction ( ϵ = 0 . 9 ) . our data , however , are better explained by low - extinction rates , that is , a pure - birth model ( ϵ = 0 ) , as opposed to a birth–death model ( ϵ = 0 . 9 ) , based on likelihood ratio tests generated in laser ( rabosky 2006a ) .
these are synodontis with shark - like fins which have made them very popular indeed . they can command quite high prices both in pet stores and out of them . these synos grow to around 12 centimeters , so they are not terribly large , and if you have the funds , you can quite happily keep several of them in a 90 gallon tank .
synodontis contractus is a small species ( 4 inches [ 10 centimeters ] ) and one of my personal favorites . it is somewhat similar in appearance to s . nigriventris but has a generally more thickset body and “chunky” build . like s . nigriventris , it will spend a good amount of its time in the inverted position and is also a schooling species .
beyond information gleaned from captive breeding of certain species of synodontis , very little is known about reproduction in mochokids . the best studied mochokids in this regard are most likely nile river synodontis ( including s . membranacea and s . batensoda , previously placed in other genera ) . still , details are limited ; the studies indicate that spawning occurs from july to october , which coincides with the flooding season , and that pairs swim in unison during spawning bouts ( bishai & abu gideiri , 1968 ) . the most interesting and detailed information on mochokid reproduction relates to a species from lake tanganyika , synodontis multipunctatus , which is a brood parasite of mouth brooding cichlids such as simochromis and haplochromis ( sato , 1986 ; wisenden , 1999 ) . adults of this species spawn in the midst of spawning cichlids and the fertilized catfish eggs are taken into the mouth of a cichlid . the catfish eggs hatch first and will eat the host eggs before they leave the host mouth . most amazingly , this species has been able to parasitize mouth brooding cichlids from south america in captivity ( loiselle , 1998 ) .
synodontis gambiensis is one of the more recognizable species that is seen regularly mixed in with shipments of catfish from the group above . it is easily spotted among such imports because it is a solid gray - colored fish . the ventral region is whitish . other identifying characteristics include whitish barbels and a somewhat indistinct dark band on each lobe of the caudal ( tail ) fin .
space considerations dictate that this article must come to a close . i have barely scratched the surface in regards to this interesting group of catfishes . i do hope that i’ve provided at least some useful information on synodontis and strongly suggest that if you haven’t kept them before , consider doing so now . i think you will receive as much enjoyment from them as i have .
based largely on coloration and pattern some scientists and aquarists have recognized ‘species flocks’ of synodontis . the largest and most visually impressive of these is the lake tanganyika synodontis species flock . the flock consists of at least six species , all endemic to the lake , that show amazingly similar coloration and patterning . recent work suggests that this ‘flock’ is not monophyletic and that the biogeographic scenario is more complicated than a simple radiation after lake formation ( day & wilkinson , 2006 ; koblmuller et al . , 2006 ) . regardless , in this group of species , the nearly constant color pattern consists of a light brown base color and darker brown polka - dots . it is made more impressive by the fins , which have dark brown membranes basally and stark white trailing edges . the cryptic nature of lake tanganyika synodontis has led to an underestimate of the actual number of species present ( wright & page , 2006 ) ; three new species were described and two others were resurrected in that work . there are several other smaller flocks with their own unique patterns and pigmentation outside of the lake , and cryptic species probably exist for these as well .
spatio , temporal distribution of synodontis scha ! l in asa lake was studied for 24 months ( march 1991 to february 1993 ) . distribution of individual was : 28 . 40 % ( surface ) , 35 . 60 % ( shore ) , and 36 . 0 % ( bottom ) . catches wilhin lhe habitat were nol significantly differen ! . similarly catches within lhe ha . . .
koblmüller , s . , sturmbauer , c . , verheyen , e . , meyer , a . , & salzburger , w . ( 2006 ) .
mitochondrial phylogeny and phylogeography of east african squeaker catfishes ( siluriformes : synodontis )
. bmc evolutionary biology 6 : 49 . doi : 10 . 1186 / 1471 - 2148 - 6 - 49 . pmc 1543664 . pmid 16784525 .
quite common , these synos reach just four inches in length , which makes them the perfect catfish for a smaller aquarium . they are known widely as the ' upside down catfish ' . they reach around 10 centimeters , or four inches and are very pretty and entertaining to watch as they defy gravity . it is best to keep this type of synodontis in groups of three or more .
dorsal view of heads illustrating sexual dimorphism of the opercular spine in synodontis acanthoperca : a . cu 89005 , male holotype , 44 . 1 mm sl ; b . cu 89006 , female paratype , 40 . 4 mm sl . the pectoral spines in both specimens have been removed from the images to make the margins of the head more distinct against the background . scale bar equals 1 mm . ©
chronogram , where synodontis are dated at either 21 . 8 ma ( blue ) or 16 . 6 ma ( green ) , with confidence limits calculated as 95 % credible intervals conditional on the tree topology . inset with ages ( and confidence limits in parenthesis ) for nodes a–g . 1 , age of lt ; 2 , onset of deep water conditions in lt ; 3 , age of lm .
the surprise is baby s . multipunctatus ! this species is by far the most commonly spawned ( in captivity ) synodontis . what makes them unique is that they will spawn in conjunction with the cichlid fish and that the female cichlids will then incubate the catfish eggs along with their own . there is not enough room here to go into detail , but do be aware that it can and does happen .
little is known about the ecology of most mochokids . what is known pertains mostly to diet and is biased towards species of synodontis . stomach contents from synodontis have included insects , nematodes , crustaceans , mollusks , annelids , seeds , algae , diatoms , fish scales and , incidentally , sand ( bishai & abu gideiri , 1965a ; bishai & abu gideiri , 1965b ; winemiller & kelso - winemiller , 1996 ; sanyanga , 1998 ) . from observations of stomach contents , the diet of most mochokids is probably very similar ; that is , they are omnivores . for some of the larger sucker - mouthed species ( i . e . , atopochilus and euchilichthys ) the stomach contents contain a high proportion of silt , algae and detritus . for these taxa it seems likely that scraping or grazing is the predominant method of feeding .
within synodontis 2 principal clades are identified ( a and b ) , which are further subdivided into the 4 main subclades ( a1 , a2 and b1 , b2 , fig . 1 ) . support for a monophyletic synodontis and main subclades based on bpps is excellent , with all major nodes except clade a ( 0 . 55 bpp ) receiving > 98 % support , with bs values slightly lower ( fig . 1 ) . support for internal nodes within the main clades is generally good , although some relationships forming the base of clade a1 are less well supported by bpp and receive no bs support . support for clade a is considerably improved ( > 0 . 95 bpp ) by the removal of the unstable sister taxa synodontis albolineatus and synodontis batesii that are sister to clade a2 ( 0 . 53 bpp ) . the position of these taxa is contentious , as while they are also placed as sister to clade a2 in the cyt b gene tree ( supplementary fig . s1b ) and mtdna tree , they are alternately sister to all other synodontis taxa in the rag2 gene tree ( supplementary fig . s1d ) . their placement in the co1 gene tree is unresolved ( supplementary fig . s1a ) , but these taxa are not resolved as sister to clade a2 as found in the cyt b tree . unfortunately , these taxa did not amplify for s7 ( supplementary fig . s1c ) . the disparity in placement of these taxa may represent insufficient data or real conflict , for example , homoplasy or cyto - nuclear discordance . however , to test between these hypotheses additional nuclear genes and samples of these taxa would need to be sequenced . support for the position of synodontis ocellifer as sister to clade b2 is weak ( 0 . 70 bpp , 57 % bs ) with this taxon also indicated as unstable using leaf stability metrics . individual gene trees for cyt b + trna - pro , coi , and s7 reveal reasonably good support for the majority of relationships identified when these data are concatenated and although there is no support for clades a1 , b1 in the co1 or s7 gene trees , there is no support for alternative hypotheses ( supplementary fig . s1b and c ) . conversely , rag 2 ( supplementary fig . s1d ) does not perform as well and yields only partial support for these clades . comparison of the concatenated tree ( p = 0 . 577 ) to the mtdna ( p = 0 . 414 ) and ncdna ( p = 0 . 000 ) trees based on au tests rejects the latter tree as a significantly worse fit to the data .
as noted above , these catfish are suitable inhabitants of malawi cichlid fish aquariums . the water conditions maintained for the cichlids are also excellent for the catfish . s . njassae is generally active enough to stay out of the way of the often aggressive cichlid fish . this synodontis appears to prefer the company of its own kind , so it would be a good idea to try to keep at least two together in an aquarium .