Titan trigger fish and its nest

Some triggerfish species can be quite aggressive when guarding their eggs. The titan triggerfish (Balistoides viridescens) viciously defend their nests against intruders, including scuba divers and snorkelers. Their territory extends in a cone from the nest toward the surface, so swimming upwards can put a diver further into the fishes' territory; a horizontal swim away from the nest site is best when confronted by an angry triggerfish. The titan triggerfish poses a serious threat to inattentive divers due to its large size and powerful teeth. A short time later I made my first experience bitten by such a monster fish.