Marine life  /  Jacks & open-water fish  /  Blue trevally
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Species entry

Blue trevally

Ferdauia ferdau

A silver jack with blue fins and scattered gold spots, over Maldivian reef and sand.

Size
To 70 cm
Depth
3–40 m
Habitat
Sand flats and reef edges
Active
Daylight
Range
Indo-Pacific
Rarity
Maldives
2 stars of 5, usually seen in a week
SP-01
blue trevally · full body · habitat
4:3 · min 2400px

To about 70 cm and 8 kg. Compressed and oblong with a bluntly rounded snout, blue-green to yellow-green above and silvery below, with five to seven broad dusky vertical bars and numerous inconspicuous golden spots mostly above the level of the pectoral fin. The soft dorsal and anal fins are pale yellow-green with white tips to the lobes.

The island trevally is the confusion and it is marked with prominent yellow spots rather than broad bars.

Nought to sixty metres over coastal sand near coral reefs, in lagoons and off beaches, singly or in small schools. It takes bottom crustaceans and molluscs more than fish, and in Hawaii it has been recorded following foraging fish and taking what they uncover. Juveniles sometimes shelter among the tentacles of large open-water jellyfish.

Ciguatera is reported, though the flesh is described as rarely poisonous. The accepted name is now Ferdauia ferdau; older guides print Carangoides ferdau.

Where to find:

LocationRarity Best monthsDepthHabitat
Maldives Maldives editorial estimate
2 stars of 5, usually seen in a week
Year-round
3–40 m
Sand flats and reef edges

Ratings are per location: 1 means found on most dives that look for it, 5 means a handful of records. Where enough dives have been logged the figure is calculated from them; otherwise it is an editorial estimate, and says so. We publish habitat and destination, not the dive site.

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