Titan Triggerfish

The titan triggerfish, giant triggerfish or moustache triggerfish (Balistoides viridescens) is a large species of triggerfish found in lagoons and at reefs in most of the Indo-Pacific, though it is absent from Hawaii. With a length of up to 75 centimetres (30 in),[1] it is the largest species of triggerfish in its range (the stone triggerfish, Pseudobalistes naufragium, from the east Pacific is larger).[2]

Characteristics
Titan triggerfish feed on shellfish, urchins,crustaceans and coral. They are the workers of the reef, often being busy turning over rocks, stirring up the sand and biting off pieces of branching coral. This is why one often sees other smaller fish species around it who feed from the left overs.

Interaction with humans
The titan triggerfish is usually wary of divers and snorklers, but during the reproduction season the female guards its nest, which is placed in a flat sandy area, vigorously against any intruders.[3] [4] Although bites are not venomous, the strong teeth can inflict serious injury that may require medical attention.[3] [4] [5] [6]

The threat posture includes the triggerfish facing the intruder while holding its first dorsal spine errect.[3] It may also roll onto its side, allowing it a better look at the intruder it perceives as threatening its nest. The titan triggerfish will not always bite, but can swim at snorkellers and divers escorting them out of their territory.

The flesh of the titan triggerfish is sometimes ciguatoxic.[3] [5]