Trigger fish get their name from two moveable spines on top of their bodies.
At night or if you disturb the fish, a trigger fish swims into a hole in the reef just big enough to accommodate its body, and is here when he use the "trigger" so predators are not able to pull him out. How it works ? Once inside, they rise the first spine locking it in place with the second spine.
These fish have powerful jaws and sharp teeth they feed on sea urchins, shells, crustaceans, mollusks, and other echinoderms, generally creatures with protective shells and spines, many will also take small fish, they are very territorial fish and defend their nests against intruders, if they feel atack will not hesitate to bite scuba divers, as the Sargent fish does as well !
Sargassum Triggerfish gets its name due to when they are young drift naer the surface in Sargassum.