Also known as
- Threadfin Trevally US
- Threadfish US
- Pennant-fish US
- African Threadfin US
Identification
A deep-bodied circumtropical wreck-and-reef bruiser that transforms with age — disc-shaped juveniles with trailing fin filaments mature into elongated muscular adult predators.
- Silvery body with a light blue metallic sheen on the back
- Small dark spot on the upper edge of the gill cover
- Juveniles display extremely long filamentous dorsal and anal fin extensions mimicking jellyfish tentacles
- Steeply rounded head profile
- Juveniles show five chevron-shaped dark bars and a black blotch at the dorsal fin base
Where it holds
- Inshore
- Coral Reefs
Behaviour
A circumtropical wreck-and-reef pelagic predator working the 30-100m depth band around offshore wrecks, deep reefs, oil platforms, drop-offs, and rocky pinnacles. Hunts mid-water and near-bottom, primarily for slow-moving crustaceans and squid, supplemented with small baitfish. Mostly solitary or in small groups; juveniles use shallow coastal water with long fin filaments mimicking jellyfish tentacles for camouflage. Most active in 16-28°C (61-82°F) water with peak activity around 25°C (77°F).
Diet: Crabs, Shrimp, Squid, Small Baitfish
How it's caught
Line Fishing
Jigging
The dominant Florida, Caribbean, Gulf, and Indo-Pacific charter approach — drop a 100-250g speed jig or slow-pitch jig (silver, white, pink, glow, often with holographic finish) over deep wrecks, oil rigs, and offshore reefs in 30-100m and work it with sharp aggressive sweeps and controlled falls. Tipping a jig with a live pilchard or cigar minnow on a 1oz jig head is deadly in shallower water. PE4-6 jigging tackle, 24-37kg braid, 80-130lb fluorocarbon leader.
Live Lining
An equally productive trophy approach — drift a live pilchard, goggle-eye, cigar minnow, sardine, pinfish, or shrimp on a 5/0-8/0 circle hook with 60-100lb fluorocarbon leader. Position up-current of the wreck or reef and drift the bait back to the structure on an inline sinker or jig head for depth control. Live chumming tightens the bite around shallow wrecks.
Trolling
An effective method when fish work shallower structure — slow-troll live or rigged dead baits at 2-4 knots near wrecks, reefs, and platforms. Inline sinkers or planers position baits in the mid-to-lower water column. Often a productive bycatch on standard pelagic trolls. PE3-4 trolling tackle, 60-80lb fluorocarbon leader.
Spinning
An effective approach when fish are marked higher in the water column or feeding around bait schools at first and last light — cast a 1-3oz bucktail jig, 5-7 inch swimbait, or compact soft plastic to marked fish or feeding bait. Vary retrieve speeds to find the strike trigger. PE3-4 spinning tackle, 60-80lb fluorocarbon leader.
Bottom Fishing
A productive approach when fish hold tight to deep structure — drop a fresh cut bait, squid, or live cigar minnow on a fishfinder rig with 8-16oz of weight to maintain bottom contact over wrecks and reefs in 60-100m. Standard mid-day approach when fish refuse jigs. PE5-6 tackle, 80-100lb fluorocarbon leader.
Spear Fishing
Bluewater Spearfishing
A challenging deep-wreck spearo target — free-dive deep wrecks, offshore reefs, and oil platforms in 30-60m where fish patrol structure. Curious yet wary; the depth window narrows the opportunity. Aim for the head or spine on the first shot. 120cm gun with triple bands and 7.5-8.0mm shaft, breakaway rig with 400lb+ shooting line. Advanced freediving skills required.
Inshore Spearfishing
An accessible approach for smaller fish on shallower coastal reefs and rocky structure in 5-15m — stalk slowly using structure for cover. Spook easily in clear water. Aim for the head. 100-110cm gun with double bands and 7.0-7.5mm shaft.
