Fish Identifier
Bluefin Trevally (Caranx melampygus) — saltwater, reef fish, pelagic
saltwater, reef fish, pelagic

Bluefin Trevally

Caranx melampygus

Deep, compressed body with a blunt head. Distinctive electric blue fins and blue speckling on upper body. Silver-white belly, forked tail, and a line of hard scutes along the rear of the lateral line. Large eye and protruding jaw.

Habitat
Tropical and subtropical waters of the Indo-Pacific.…
Size & weight
Commonly 40-70 cm; can reach maximum length of 117 cm an…
Diet
Carnivorous opportunistic predator;…
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Physical characteristics

Deep, compressed body with a blunt head. Distinctive electric blue fins and blue speckling on upper body. Silver-white belly, forked tail, and a line of hard scutes along the rear of the lateral line. Large eye and protruding jaw.

Habitat & distribution

Tropical and subtropical waters of the Indo-Pacific. Found from coastal reefs and estuaries to deep seaward reefs and offshore islands; ranges from 1 to 190 meters deep.

Behavior

Highly active diurnal predator. Often seen in small schools or as solitary individuals. May follow larger species like sharks or rays to snatch prey they disturb.

Diet

Carnivorous opportunistic predator; feeds mainly on small fish, but also cephalopods and crustaceans. Uses high-speed pursuit and ambush tactics.

Reproduction

External spawners; reach sexual maturity at around 30-40 cm. Spawning occurs in large aggregations near reefs or offshore banks. Pelagic larvae.

Ecological role

Top-level predator on coral reefs; regulates populations of small fishes and crustaceans; host to various parasites.

Similar species

Giant Trevally (larger, lacks blue fins/specks), Brassy Trevally (lacks blue fins, has brassy coloration/fewer spots).

Identification tips

Look for the brilliant electric blue coloration on the second dorsal, anal, and caudal fins. Small black-to-blue spots on the upper flanks are diagnostic.

Interesting facts

Unlike most jacks that are silvery, this species is known for its remarkable neon-blue highlights. It is a popular species for catch-and-release sport fishing due to its extreme power and endurance.