Trevallys are large silvery fishes with forked tails. They are fast-swiming predators of the waters above the reef and in the open sea.
The species we are concentrating on today, the Bluefin Trevally, is found in the Red Sea and Pacific Ocean. It is distinctively coloured, being the only trevally with electric blue fins and blue speckles on a gold or green background.
This fish can be as large as 1 metre, but you normally see individuals smaller than this. They range from the shallows to the depths, usually singly but you may see a trevally small school.
Bluefin Trevally are currently being trialled for aquaculture in the Pacific. But if eating this fish beware of large specimens: they become toxic when over 50 cm.
The fish feeds on other fish and sometimes crustaceans. It launches high-speed attacks, typical of large transient predators. However, when feeding on spawning fish it also ambushes its prey, attacking from a hiding place. This is unusual in such a fast-swimming fish. During ambush hunting, it adopts a dark coloration and defends a section of the reef.