Contrary to pupular folkflore, parrotfish do not get their name from their beautiful rainbow of colors, instead these fish get their name from their teeth. These teeth are joined to form a parrot's beak in the front of the mouth. Nobody knows how many species there are in the world (350 have been named, but there probably fewer than 80).
Parrotfish live around tropical reefs. The average adult sizes vary from 1 to 6 fet long (some have been know to reach 12 feet in length).
When merely cruising around they swim with their pectoral fin using their tail only when they need to swim a bit faster.
Parrotfish of the genus Sparisoma may live solitary lives or may gather in small groups without any social organisation. Some species of the genus Scarus move about in large groups of up to 40 fish when feeding. Because of this parrotfish are sometimes referred to as the "cattle of the sea". Often they are seen near the shore with their backs out of the water. The schools are made up of many fish, all about the same size (the smallest keeping together the medium size fish keeping together and the largest keeping together) In some species of the genus Scarus the groups are smaller and are made up of several females with a mature male acting as the leader, like cows with a bull. Should another male join the group he will be chased away, the leader sometimes chases the intruder 20 feet away for a distance of 100 yards before rejoining the his harem.
For a long time parrotfish were seperated into species on the basis of color. Then it was found that the same species would be found in a different color during the course of it's lifetime. In others there is a marked difference between male and female. For example Scarus taenioperus is striped with orange and blue while Scarus croicensis is striped brown and white. Then scientists realized that both belonged to the same species, S. taenioperus being male and S. croicensis being being female. This was tested by taking the female parrotfish and injecting them with male sex hormones. Injected S. croincensis turned from brown and white striped (female colors) to blue and oranged striped (male colors). Where males and females are differently colored, the young parrotfish are colored like the females (brown and white striped). As they mature the females keep their colors and the males take on the colors of the mature males. Another change that can take place with age, in some parrotfish, is that the males become bumpheaded. Instead of the forehead sloping forward it becomes a large bump.