Reef triggerfish

The triggerfish's teeth and top lip are blue and the teeth are set close together inside its relatively plump mouth. The fish has a small second spine, which it can use to lock its main spine into an upright position. Locking its spine while sheltering inside a small crevice makes it difficult for a predator to pull the fish out. When fleeing from predators, the triggerfish will sometimes make grunting noises, possibly a call to warn other nearby triggerfish of danger. The triggerfish can blow jets of water from its mouth, which help the fish find benthic invertebrates that may be buried under the substrate. Triggerfish can often be seen spitting sand from their mouths in order to sift through the material in search of edible detritus or organisms. Reef triggers, up to 30 cm in length, are fairly aggressive and will generally not tolerate conspecific individuals in their general vicinity; thus the fish is often found solitary. This is particularly true in captivity. Triggers have the ability to rapidly alter their coloration. They can fade into a relatively drab appearance when sleeping or demonstrating submission, while their coloration is often the most vivid when the fish are healthy and unthreatened by their surroundings. They have also been known to bite and attack swimmers in their area, sometimes leaving marks often on the ankle area.