The surgeonfish have compressed bodies and all have a sharp spine on either side of the body near the base of the tail. The spines are usually folded into a groove but, when the fish is threatened, the spines are lifted and used to slash at the attacker. Most fish in this family are herbivorous and graze on algae while a few feed on plankton or on detritus. Most live in warm tropical waters and are often found on coral or rocky reefs.
