What Divers Should Know About Giant Trevally

The giant trevally (Caranx ignobilis) stands as an apex predator throughout its tropical Indo-Pacific habitats. This impressive jack is the largest in its genus, reaching a maximum known size of 170 cm (67 in) and 80 kg (176 lb). Adults are typically encountered patrolling deeper reefs, offshore atolls, and large embayments, making them a significant presence on many dives.

Recognizable by its steep head profile and strong tail scutes, the species is normally silvery with occasional dark spots. Mature males, however, can be distinctly black. Often observed individually or in dynamic schools, their active predatory behavior, which includes unique hunting strategies, can be witnessed in open water or along reef edges. These fast-growing fish reach sexual maturity around 60 cm at three years of age, often congregating over reefs and bays to spawn during warmer months.