Goatfish

Thegoatfishesareray-finned fishof the familyMullidae, the only family in the suborderMulloideiof the orderSyngnathiformes.The family is also sometimes referred to as thered mullets, which also refers more narrowly to the genusMullus.
The family name and the English common name mullet derived from Latinmullus, thered mullet; other than the red mullet and thestriped red mulletor surmullet, the English word "mullet" generally refers to a different family of fish, theMugilidaeor gray mullets.
Goatfish are characterized by two chin barbels (orgoatee),  which contain chemosensory organs and are used to probe the sand or holes in the reef for food. Their bodies are deep and elongated, with forked tails and widely separateddorsal fins.The first dorsal fin has six to eight spines; the second dorsal has one spine and 8–9 soft rays, shorter than anal fin. There are one or two spines in the anal fin with five to eight soft rays. They have 24 vertebrae.
Many goatfish are brightly colored. The largest species, thedash-and-dot goatfish(Parupeneus barberinus), grows to 60 cm (24 in) in length; most species are less than half this size. 
Within the family are sixgeneraand about 86species.
These genera are classified as belonging to the Mullidae:
Goatfish are distributed worldwide in tropical, subtropical, and temperate waters, in a range of habitats. Most species are associated with the bottom of thelittoral, but some species ofUpeneuscan be deep; for example, the goatfishUpeneus davidaromican be found at depths of 500 metres (1,600 ft). Tropical goatfish live in association with coral reefs. Some species, such as thefreckled goatfish(Upeneus tragula), enterestuariesandrivers, although not to any great extent.
Goatfish arebenthicfeeders, using a pair of longchemosensorybarbels(whiskers) protruding from their chins to feel through the sediments in search of prey.They feed onworms,crustaceans,molluscsand other smallinvertebrates. Other fish shadow the active goatfish, waiting patiently for any overlooked prey. For example, in Indonesia large schools of thegoldsaddle goatfish(Parupeneus cyclostomus) and moray eels hunt together. This behavior is known as shadow feeding or cooperative hunting.
By day, many goatfish will form largeschoolsof inactive (nonfeeding) fish; these aggregates may contain both conspecifics and heterospecifics. For example, the yellowfin goatfish (Mulloidichthys vanicolensis) is often seen congregating withbluestripe snappers(Lutjanus kasmira). 
All goatfish have the ability to change their coloration depending on their current activity. One notable example, the diurnalgoldsaddle goatfish(Parupeneus cyclostomus) can change from a lemon-yellow to a pale cream whilst feeding.
Goatfish have the ability to rapidly change color, and many species adopt a pale coloration when resting on the sand to blend with the background and become less visible to predators. These changes in color are reversible phenotypic changes and happen within seconds, many times during the lifespan of an individual.
Two species, the mimic goatfish (Mulloidichthys mimicus) and Ayliffe's goatfish (Mulloidichthys ayliffe) have evolved to mimic the blue-striped snapper (Lutjanus kasmira), with which they often form schools. These are slow, genetic changes that have occurred during their evolution over many generations.
Goatfish are pelagic spawners; they release many buoyant eggs into the water, which become part of theplankton. The eggs float freely with the currents until hatching.
The larvae drift in oceanic waters or in the outer shelf for a period of 4–8 weeks until they metamorphose and develop barbels. Soon thereafter, most species take on a bottom-feeding lifestyle, although other species remain in the open water as juveniles or feed on plankton.Juvenile goatfish often prefer soft bottoms, in seagrass beds to mangroves. They change habitat preference as they develop, coinciding with changes in feeding habits, social behavior, and the formation of association with other species. Most species reach reproductive maturity after 1–2 years.
Goatfish species are an important fishery in many areas of the world and some species are economically important. 
In ancient Rome until the end of the second century BCE, two species of goatfish (Mullus barbatusandMullus surmuletus) were highly sought-after and expensive, not as a delicacy, but for aesthetic pleasure, since the fish assume a variety of colors and shades also during death. Therefore, it was paramount to serve the fish live and let them die before the eyes of the guests.