Goatfish
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Mulloidichthys |
Goatfish are tropical marine perciform fish of the family Mullidae. Seldom found in brackish waters, goatfish are most associated with the reefs of the Atlantic, Indian, and Pacific Oceans. Within the family are approximately six genera and 55 species.
Many species of goatfish are conspicuously coloured; however, they are not popular in aquaria. Rather, goatfish are valued food fish in many countries. The largest species, the dash-dot goatfish (Parupeneus barberinus) grows to 55 centimetres in length; most species are less than half this size. Their bodies are deep and elongate with forked tail fins and widely separated dorsal fins.
Perhaps the goatfish's unpopularity among fishkeepers can be attributed to its feeding habits: Goatfish are tireless benthic feeders, using a pair of long chemosensory barbels ("whiskers") prodtruding from their chins to rifle through the sediments in search of a meal. Like goats, they seek anything edible; worms, crustaceans, molluscs and other small invertebrates are staples.
By day, many goatfish will form large inactive (non-feeding) schools: these aggregates may contain both conspecifics and heterospecifics. For example, the yellowfin goatfish (Mulloidichthys vanicolensis) of the Red Sea and Hawaii is often seen congregating with blue-striped snappers (Lutjanus kasmira). With such mixed company, the yellowfins will actually change their coloration to match that of the snappers.
By night the schools disperse and individual goatfish head their separate ways to loot the sands. Other nocturnal feeders will shadow the active goatfish, waiting patiently for any overlooked morsels. Goatfish stay within the shallows, going no deeper than about 110 metres. Some species, such as the freckled goatfish (Upeneus tragula) of East Africa, have been known to enter estuaries and rivers, although not to any great extent.
All goatfish 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. Diurnal species also tend to be solitary, but will school as juveniles.
Goatfish are pelagic spawners; that is, they release many buoyant eggs into the water which become part of the plankton. The eggs float freely with the currents until hatching.
External links
- FishBase entry on Mullidae (http://www.fishbase.org/Summary/FamilySummary.cfm?ID=332)