The family name and the English common name "mullet" name are derived from Latin mullus, the red mullet; but additional than the red mullet and the striped red mullet or surmullet, the English word mullet generally refers to a different family of fish, the Mugilidae or grey mullets.
Goatfishes are characterised by a pair of chin barbels, 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 separated dorsal fins. The first dorsal fin has 6-8 spines; the second dorsal has one spine and 8-9 soft rays, shorter than anal fin. Spines in anal fin 1 or 2, with 5-8 soft rays. They have 24 vertebrae.
Many goatfishes are brightly colored. The largest species, the dash-and-dot goatfish (Parupeneus barberinus), grows to 60 cm in length; most species are less than half this size. Within the family are six genera and about 86 species.
Distribution and habitat
Goatfishes are distributed worldwide in tropical, subtropical and temperate waters. Goatfishes occur in a range of habitats. Most species are associated with the bottom of the littoral, but a few species of Upeneus can be deep; for example the goatfish Upeneus davidaromi can be found to depths of 500 m. Tropical goatfishes live in association with coral reefs. Some species, such as the freckled goatfish (Upeneus tragula) enter estuaries and rivers, although not to any great extent.
Goatfishes are tireless benthic feeders, using a pair of long chemosensorybarbels ("whiskers") protruding from their chins to rifle through the sediments in search of prey. They feed on worms, crustaceans, molluscs and additional small invertebrates. Other fish shadow the active goatfish, waiting patiently for any overlooked prey. For example, in Indonesia large schools of the l goldsaddle goatfish (Parupeneus cyclostomus) and moray eels hunting together. This behaviour is known as shadow feeding or cooperative hunting. By day, a large number of goatfishes will form large schools of inactive (non feeding) fish; these aggregates might contain both conspecifics and heterospecifics. For example, the yellowfin goatfish (Mulloidichthys vanicolensis) is often seen congregating with bluestripe snappers (Lutjanus kasmira). All goatfishes have the ability to change their coloration depending on their current activity. One notable example, the diurnal goldsaddle goatfish (Parupeneus cyclostomus) will change from a lemon-yellow to a pale cream whilst feeding.
Goatfishes have the ability to rapidly change color, and a large number of species adopt a pale coloration when resting on the sand to blend with the background and become less visible to predators. These changes in colour are reversible phenotypic changes and happen within seconds a large number of times throughout the lifespan of an individual.
Two species of goatfishes, the mimic goatfish Mulloidichthys mimicus and Ayliffe's goatfish Mulloidichthys ayliffe have evolved to mimic the blue-striped snapper Lutjanus kasmira, with whom they often form schools. These are slow, genetic changes that have occurred throughout the evolution of goatfishes over a large number of generations.
Reproduction and life cycle
Goatfishes are pelagic spawners; they release a large number of buoyant eggs into the water which become part of the plankton. The eggs float freely with the currents until hatching. The larvae drift in oceania waters or in the outer shelf for a period of 4–8 weeks until they metamorphose and develop barbels. Soon thereafter most species take of bottom-feeding life-style, although additional species remain in the open water as juveniles or feed on plankton. Juvenile goatfishes often prefer soft bottoms, in seagrass beds to mangroves. They change habitat preference as they develop, coinciding with changes in feeding habits, social behaviour and the formation of association with additional species. Most species reach reproductive maturity after one or two years.
Goatfish species are an important fishery in a large number of areas of the world and a few species are economically important. In ancient Rome until the end of the second century AD, two species of goatfish (Mullus barbatus and Mullus surmuletus) were highly sought-after and expensive, not as a delicacy, but for aesthetic pleasure, after the fish assume a variety of colours and shades additionally throughout death. Therefore, it was paramount to serve the fish live and let them die before the eyes of the guests.