Any of some 300 species (family Labridae) of slender, often brilliantly coloured, fishes, found worldwide in tropical and temperate seas, often on coral reefs. Species range from 2 in. (5 cm) to 7 ft (2 m) long. Wrasses have thick lips, large scales, long fins, and large, often protruding, canine teeth. Most eat invertebrates; some species, called cleaner wrasses, pick off and eat the external parasites of larger fishes. The tautaug (Tautoga onitis) is an edible species.
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Some wrasses are widely known for their role as symbiotic fish, similar to the actions and those ascribed to the Egyptian plover: other fish will congregate at wrasse cleaning stations and wait for wrasses to swim into their open mouths and gill cavities to have gnathiid parasites removed. The cleaner wrasses are best known for feeding on dead tissue and scales and ectoparasites, although they are also known to 'cheat' through the removal of healthy tissue and mucus, which is costly for the client fish to produce. The bluestreak cleaner wrasse, Labroides dimidiatus is one of the most common cleaners found on tropical reefs. Few cleaner wrasses have been observed being eaten by predators, possibly because the removal of parasites from the predator fish is more important for the survival of the predator than the short-term gain of eating the cleaner (see Trivers, R. L. 1971).
Other species of wrasse, rather than having fixed cleaning stations, specialize in making "house calls"—that is, their "clientele" are those fish that are too territorial or shy to go to a cleaning station.