Distinctive Characters: Dorsal fins close together, the first with 13-15 spines, its margin nearly straight, the second followed by 6-7 finlets. Anal fin with 12-13 rays followed by 6 finlets. Pectoral fin with 25-28 rays. Body elongate and moderately compressed. Mouth fairly large. 14-31 large conical teeth on both jaws. Interpelvic process large and single. Lateral line strongly undulating.
Colour: Overall appearance grey. Back blue-black, fading to silvery below. Anterior edge of first dorsal fin dark, other fins grayish. Tips of second dorsal and anal white.
Habitat and Biology: An epipelagic species, usually encountered around coral reefs. Generally solitary, or occurs in small groups. Voracious predator, feeding on small schooling fishes and squids.
Remarks: Unlike other tunas, which are more or less fishes of open ocean. Gymnosarda unicolor is usually associated with coral reefs. It is caught by trolling and handlining. A wide size range is landed at Male�? fish market but most are within the range 40-110 cm fork length.