Bluefin Trevally
Caranx melampygus
Type: saltwater, reef fish, pelagic
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.
Size & Weight
Commonly 40-70 cm; can reach maximum length of 117 cm and weight up to 43.5 kg.
Similar Looking Species
Giant Trevally (larger, lacks blue fins/specks), Brassy Trevally (lacks blue fins, has brassy coloration/fewer spots).
Ecological Role
Top-level predator on coral reefs; regulates populations of small fishes and crustaceans; host to various parasites.
Diet
Carnivorous opportunistic predator; feeds mainly on small fish, but also cephalopods and crustaceans. Uses high-speed pursuit and ambush tactics.
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.
Reproduction
External spawners; reach sexual maturity at around 30-40 cm. Spawning occurs in large aggregations near reefs or offshore banks. Pelagic larvae.
Conservation Status
Least Concern (IUCN); population status is stable globally but heavily pressured in localized regions.
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.
Identified on: 5/19/2026
Mode: Standard