The Parrot Fish belongs to one of the 80 species of fishes of the family Scaridae (order Perciformes) found on tropical reefs.
Parrot fishes are elongated, usually rather blunt-headed and deep-bodied, and often very brightly coloured. They have large scales and a characteristic birdlike beak formed by the fused teeth of the jaws. The beak is used to scrape algae and the soft part of coral from coral reefs and is strong enough to leave noticeable scars in the coral. The parrot fishes grind their food and bits of coral with platelike teeth in their throats.
Parrot fishes range to a length of about 1.2 metres (4 feet) and weight of about 20 kilograms (45 pounds), or occasionally larger. They are variable in colour, the male of a species often differing considerably from the female, and the young may differ from the adult.
Parrot fishes may be shades of blue, green, yellow, or other colors, with entirely different colors and patterns at each life stage. Parrot fishes have the unusual ability to change gender. The female bicolor parrot fish may have been a male in the past, or may transform into a male soon. When a female becomes a male, the resulting secondary male colors are the most colorful. In fact, most of the brilliantly colored individuals with elaborate designs are probably parrot fish that have changed into males. The life stages are so distinct that members of the same parrot fish species have frequently been misclassified as multiple species.
Although related to carnivorous wrasses, parrot fishes are herbivorous, usually grazing among coral reefs. They feed on algae, which they bite off from coral using their heavy parrotlike beaks. Their beaks are so strong that they actually bite off chunks of hard coral. Some parrot fish have the unusual habit of secreting a mucous sac around their bodies at night and emerging from it in the morning.
Parrot fishes are edible but are not, as a group, of great economic importance. The surf, or rivulated, parrot fish (Callyodon fasciatus) is an Indo-Pacific representative of the family; it grows to 46 centimetres (18 inches) or more, and the male is green and orange or red, the female blue and yellow. Atlantic species include the rainbow parrot fish, which grows to about 90 centimetres and is bright orange and green with a blue beak, and the queen parrot fish (Scarus vetula), which grows to about 50 centimetres and is blue with green, red, and orange if male but reddish or purplish with a white stripe if female.
"parrot fish." Encyclopędia Britannica from Encyclopędia Britannica 2007 Ultimate Reference Suite. (2007).