Eel
* All eels have nematodes inside, but the nematodes only burrow out when the eel is unhealthy
  - teeth and can make short work of nylon and braid
* Many eels migrate over long distances to breed and to eat.
* Most eels absorb oxygen.
* Most eels are catadromous
  - predators
  - catch fish
  - eat meat
* Most eels enter fresh water
* Most eels have gills
  - jaws
  - no scales and are protected by a layer of slippery mucus
  - organs
  - respiratory organs
  - skin
* Most eels live in dark water
  - muddy water
  - salt water
* Most eels occupy aquatic habitats
  - prefer to live in the shallowest parts of the ocean
* Some eels eat dead fish
  - krill
  - worms
* Some eels have eels
  - electricity
  - fins
  - habitat requirements
  - habits
  - senses
  - texture
  - live in salt water, but many also live in fresh water
  - move back and forth between fresh water and ocean environments
* Some eels produce electricity
  - voltage
  - return to oceans
  - seem to develop an unnatural appetite, which means they put on a lot of weight
  - show fossil evidence
* Some eels undergo final metamorphosis
  - phases
  - several phases
  - wait for animals.
  * have fewer fins than other fish. They do not have all the belly and chest fins. The back and anal fins are long and usually connected to the tail fin. The fins do not have spines.
  * hatch from eggs. A young eel is called an 'elver'. For a long time people did not know where eels came from, because baby eels look very different from adults. They thought the babies were a different species.
  * Most eels prefer to live in the shallowest parts of the ocean. They live at the bottom of the ocean, sometimes in holes. Eels in the 'Anguillidae' family come to fresh water to there.
  * Most eels are predators. They hunt their prey
* abound in the ancient drainage ditches, known locally as rhynes.
* also eat invertebrates, crustaceans, shrimp, crabs and sea urchins
  - serve as animal fodder, fertilizer and an ingredient in some glues
* apparently have relatively small home ranges within which they forage.
* are active and reclusive, nocturnal and physically extremely hardy
  - actually fish that come up rivers and streams from the ocean to spawn
  - all predators that enjoy whole shrimp, clams, or fish about twice a week
  - also colored either brown, dark green or gray
  - an important food source in many areas
  - bottom dwellers
  - carnivores and, contrary to earlier thinking, seek living rather than dead organic matter
* are catadromous, swimming down
  - which means they spawn in saltwater and mature in freshwater
  - common residents of Hawaiian reefs
  - especially well suited to being raised in artificial ponds
  - fish and use gills to breathe, whereas sea snakes are reptiles and use their lungs
  - fish, and fish have a skeleton
  - generally predators and carnivores, and sometimes they're cannibals
  - important commercial fish in New York State
  - long and thin like snakes
  - nocturnal and most of their feeding therefore occurs at night
  - opportunistic feeders and consume a wide range of food items
  - particularly vulnerable if deep hooked, as all their vital organs are close to the throat
  - quite common during late evening and night fishing
  - regarded as a source of stamina for men in Korea
  - scavengers and eat virtually anything dead or alive
  - secretive and employ stealth as a primary hunting technique
  - the only catadromous species in the Bay
  - unclean because they are fish without scales
* bony fish
* can also alter their coloration in response to changes in illumination and background
  - breathe through their skin when out of water
  - live in saltwater or fresh water
* constitute one of a few fish species known as troglophiles that can live in underwater caves.
* descend rivers and seek the mid-ocean to spawn.
* do wander overland, especially in the wet stormy nights they prefer for migration.
* eat a wide variety of live and dead food
  - invertebrates, fish, and other eels
* feed mainly on invertebrates, crustaceans, small fish and insect larvae
  - on fish, worms, insects, and snails
* hatch from eggs that the the female lays
* have a highly distinctive-looking, elongated body
  - terminal mouth, extending posteriori to or beyond the eye
  - very long cylindrical body which is very muscular
  - leathery skin, and a long fin down their back and up their belly
* have many predators, including large fish and seabirds
  - traits that suggest a lively intelligence
  - one of the most highly developed senses of smell among animals
* have poor eyesight and depend on their smell
  - rely heavily on their sense of smell
  - quite a complex life cycle
* hide from otters
  - within the reef's crevices during the day and then hunt during the night
* lack the large gill covers found in true fishes.
  - freshwater but migrate to the ocean to breed
* produce rhythmic ripples down the lengths of their bodies.
* provide much more than just food for human consumption.
* range in size from small to very large and a bite, from even a small one is cause for concern.
* rely heavily on their sense of smell rather than sight to detect their prey.
* reproduce in salt water and grow to maturity in fresh water streams and lakes
  - saltwater and grow to maturity in freshwater streams and lakes
* show a pattern of fiber type recruitment with swimming speed common to many fish.
* tend to hide in crevices during the day with only their head visible.
* then enter our rivers as small juveniles that are known as glass eels.
* usually feed on living organisms like plankton
  - spend ten years in freshwater before returning to the sea to spawn