Titan Triggerfish

The titan triggerfish, also known as the giant triggerfish or moustache triggerfish (Balistoides viridescens), is a substantial species of triggerfish found in lagoons and reefs up to depths of 50 m (160 ft) across the Indo-Pacific region, excluding Hawaii. It holds the title of being the largest triggerfish species in its habitat, with a maximum length of 75 centimetres (30 in). However, the stone triggerfish (Pseudoundefinedstes naufragium) found in the eastern Pacific surpasses it in size.

This species of triggerfish is diurnal and solitary in nature. It sustains itself by consuming sea urchins, molluscs, crustaceans, tube worms, and coral. Its feeding behavior often involves turning over rocks, stirring up sand, and nibbling on pieces of branching coral. Consequently, smaller fish species are often found in close proximity, taking advantage of the stirred-up detritus and smaller organisms.

Titan triggerfish have displayed aggressive behavior towards other fish that encroach upon their territory. While they are generally cautious around divers and snorkelers, female triggerfish can become territorial and aggressive during their reproductive season, which occurs for about a week each month, usually following the full moon or new moon, depending on the population. The nesting site is typically situated in a flat sandy area and fiercely guarded against intruders. The boundary of the territory around the nest has a cone-like shape, and divers who accidentally enter it risk being attacked. In such situations, divers should swim horizontally away from the nest rather than upwards, which would only result in further trespassing. Although the bites of titan triggerfish are not venomous, their strong teeth can cause severe injuries that may require medical attention. The triggerfish assumes a threat posture by facing the intruder while raising its first dorsal spine erect. It may also roll onto its side to obtain a better view of the perceived threat to its nest. While the titan triggerfish may not always resort to biting, it may swim aggressively towards snorkelers and divers to escort them out of its territory.

It is worth noting that the flesh of the titan triggerfish can be ciguatoxic, posing a risk to human consumption.