Side by Side

Bluefin Trevally (Omilu) Caranx melampygus

Typical: 14–24 in, 2–10 lb

Quickest tell: Bright blue fins plus fine black-and-blue speckling across the back instantly mark Omilu, versus the plain grey, steep-headed Ulua.

• Electric blue to blue-green fins (second dorsal, anal, and tail)
• Numerous small black and blue spots scattered over the upper body and head
• Silvery body with a bluish sheen
• Hard bony scutes along the rear lateral line near the tail
• Forked tail; head profile sloping, less steep than Ulua

Full Bluefin Trevally (Omilu) guide — season, gear and rules →

Ulua (Giant Trevally) Caranx ignobilis

Typical: 24–40 in, 10–40 lb

Quickest tell: Steep blunt forehead, large size, and a plain silver-to-grey body with no blue fins and no spots separate it from the spotted, blue-finned Omilu.

• Steep, blunt, near-vertical head profile
• Silver to dusky-grey body; large adults darken toward black
• Hard bony scutes (keeled scales) along the rear lateral line at the tail base
• Deeply forked tail; first dorsal of soft rays low and even
• No spots, bars, or blue fins (uniform; dominant/males may flush dark)

Full Ulua (Giant Trevally) guide — season, gear and rules →

When Each Is Running July — current month highlighted

Where Bluefin Trevally (Omilu) and Ulua (Giant Trevally) Overlap

Both run in Hawaiian Islands — that is where telling them apart actually matters.

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