The blue trevally, Carangoides ferdau, (also known as the banded trevally, barred trevally, Ferdau’s trevally and Forskaal’s jackfish) is a common, widespread species of pelagic marine fish classified in the jack family, Carangidae. The blue trevally is distributed throughout the tropical and subtropical waters of the Indo-Pacific and central Pacific regions, ranging from South Africa in the west to Hawaii in the east. It is a moderately large fish, growing to a recorded maximum length of 70 cm, with the number of rays in the second dorsal fin and the colouring serving as diagnostic features of the species. The species inhabits waters to depths of 60 m, generally inhabiting reefs, beaches, lagoons, and areas with sandy substrates. It is a predatory fish, taking other fish, prawns, crabs, and molluscs, and very little is known of the species' reproductive biology. The blue trevally is of varying importance to fisheries throughout its range, with some regions having high catches of the fish. It is considered to be a gamefish, and is sought after for its excellent eating qualities.