yellowmargin triggerfish

This triggerfish can reach a length of 60 centimeters. It can be easily recognized by the yellow-orange coloration present in the margins of its anal, caudal, and second dorsal fins.

Its body is oval and laterally compressed, the skin is covered with large and small scales that form a cluster. Like other triggerfish, it undergoes color changes during its development. Juveniles have a yellow belly with dark marbling. Later, they become greenish with black spots and eventually as adults, they lose their marbling to reveal yellow margins surrounding the fins.

The first dorsal spine is formed of three spiny rays, the first of which can be locked in an upright position while the second locks this first one. This mechanism is very useful as a deterrent for predators. It can also use it to find refuge in a cavity and once inside, it unfolds its fin to be protected from currents.

The second dorsal fin has between 24 and 27 soft rays, almost symmetrical to the anal fin. The pelvic fin is reduced to a small protuberance.

The eyes, independent, are small and located very high on the head. The mouth is small relative to the head size, but it is equipped with incisor teeth capable of breaking shells.

Generally, this species is solitary except during the nesting period. Juveniles can be seen in small groups.

Their diet mainly consists of coral branches, gastropods, crustaceans, foraminifera, tunicates as well as sea urchins. They also feed on algae.

Like other triggerfish, it defends its territory during the breeding season and can become aggressive.

This fish is oviparous. During the breeding season, males migrate to a spawning area where they establish nesting territories. It takes place in sandy-bottom channels and shallow cuts through the coral reef. Generally, the nest consists of depressions reaching 2 meters wide and 0.7 meters deep.

Then females arrive a few days later and select a male for mating. A female of this species can lay up to 430,000 eggs, in a spongy cluster the size of a fist, weighted down with rubble.

Both parents protect the spawn and provide care but only the females tend to the eggs. The juveniles are pelagic. They remain at the surface, camouflaged in brown algae such as sargassum.