They have continuously growing teeth that grind up coral and coralline algae. After they have eaten and digested the edible portions, they excrete it as sand. One single parrotfish can excrete up to 200lb of sand and they have helped to create small islands and the beautiful, sandy beaches of the Caribbean.
Their many teeth are tightly packed on the outside surface of their jaw bone, resembling the beak of a parrot. They use their unique beaks to eat algae off of coral and rocks, contributing to a process known as bio-erosion, and this also helps to prevent algae from chocking the coral reefs.
The main predator of parrotfish are the lemon shark and moray eel. Parrotfish have to be on a constant lookout for these creatures while feeding. To protect themselves while sleeping, they extrude mucus from their mouths and cover their bodies with a cocoon of it to hide their scent from predators.
It is important that parrotfish are protected if the Caribbean coral reefs are to be saved from being overgrown by seaweed. Unfortunately, these brightly colored fish can not be kept in marine aquaria because their feeding habit renders them unsuitable for such an environment.
