FishCommonVisible while snorkeling

Bluefin trevally

Caranx melampygus

It slices along the reef edge on electric-blue fins – one of the Red Sea's fastest and most spectacular hunters.

Photo: iNaturalist – (c) David R, some rights reserved (CC BY-NC), uploaded by David R

The bluefin trevally (Caranx melampygus) is the fish that makes it worth glancing into the blue every now and then during a dive. Its streamlined silvery body is dusted with tiny black and neon-blue speckles, and its fins glow a brilliant electric blue – in sunlight it flashes past like a polished metal rocket. Older individuals turn ever bluer: the big veterans gleam azure over nearly their whole body.

It is a thoroughbred open-water predator, patrolling the reef edge and striking small schooling fish with lightning charges – clouds of fusiliers and glassfish are its favourites. While hunting, its colours visibly darken; the excitement is literally written on its skin. It often hunts in pairs or small squadrons and even forms alliances with other species, trailing moray eels and octopuses to snap up the fish they flush from hiding.

Around Hurghada you meet it most often at current-swept reef corners and along walls dropping into the deep – sometimes as a single flash, sometimes as a small hunting party. It can sweep past you over the shallower plateaus while snorkeling too. It does not give divers a wide berth: it sizes up your bubble cloud with quick, curious circles, then vanishes into the blue as suddenly as it came.

Did you know?

The bluefin trevally is one of the sea's best "team players": it regularly attaches itself to hunting morays and octopuses, snapping up the fish that flee their hiding places – researchers rank this cross-species alliance among the most sophisticated hunting strategies in the ocean.

Where can you meet it?

It favours current-swept reef edges: it turns up on almost every dive along the walls of the Giftun Islands and Small Giftun, the Carless Reef plateau and the corners of Umm Gamar.

Frequently asked questions

Do not search the coral – watch the blue water: it patrols along the reef edge and the current-swept corners. The best moments come when a school of fusiliers suddenly contracts – chances are a hunting trevally has just charged into them.

Not at all: the trevally hunts small fish and is at most curious about divers. That flashing blue body sweeping past is one of the most beautiful sights underwater – keep your camera ready, because it is faster than you think.

The trevally can shift its shade in seconds using pigment cells in its skin: while hunting or excited it darkens dramatically, turning almost blackish blue. If you see a dark, fast shadow darting around the schools, you are watching it in action.