Fin's Fish Guide
The Black jack (Caranx crysos) is a brackish-water fish of the family Carangidae that grows up to 70 cm.
Eastern Atlantic from Senegal to Angola and the Mediterranean Sea; western Atlantic from Nova Scotia to Brazil, the Gulf of Mexico and the Caribbean.
Description
The blue runner is a streamlined predator of the family Carangidae reaching about 70 cm. The back is light olive to blue-green, the flanks silvery-grey to golden; juveniles show about seven dark cross-bars. The species has two dorsal fins, sickle-shaped pectoral fins and a deeply forked tail. It lives in schools, usually not far from the coast, in the eastern and western Atlantic and the Mediterranean, to about 100 m. The blue runner hunts fish, shrimp and other invertebrates. It spawns offshore with pelagic eggs and is a valued food fish, though it can locally cause ciguatera poisoning when eaten.
Frequently asked questions
How do you recognise the Black jack?
The Black jack has a torpedo-shaped body, is mainly blue and shows a plain pattern. Streamlined jack with an olive-green to bluish back and silvery-golden flanks; juveniles with seven dark vertical bars. Note: in tropical areas this species can cause ciguatera poisoning when eaten; large specimens of coral reef predators can accumulate the toxin. Eat with care or avoid in risk areas.
Where does the Black jack live?
The Black jack lives in brackish water and is mostly found around stony or rocky ground. Eastern Atlantic from Senegal to Angola and the Mediterranean Sea; western Atlantic from Nova Scotia to Brazil, the Gulf of Mexico and the Caribbean.
How big does the Black jack get?
The Black jack grows to a maximum of about 70 cm. On average the species is around 40 cm.
Is the Black jack dangerous to humans?
The Black jack is venomous — handle spines with care and seek medical help after a sting if needed. Harmless to handle, but may cause ciguatera poisoning if eaten; seek medical help if symptoms such as nausea or tingling occur.
Is the Black jack edible?
Yes, the Black jack is commonly eaten.
More photos
Easily confused with
These species look like the Black jack and live in the same waters.
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All data
Identification
Appearance
Habitat & distribution
Behaviour & biology
For anglers
Safety
Status & sources
Same genus Caranx
More from the family Carangidae
Want the complete picture on the Black jack?
Point your camera at the fish and Fin names the species in seconds. Free, and the Black jack is one of 12,519 species in the app.