
The Diamond Trevally has a compressed body and a long straight snout. It has a large forked tail and long curved pectoral fins. The anterior section of the dorsal fin has long filaments in juveniles.
This species is silvery with a blue-green tinge above. Juveniles have five to seven broad, dark bands.
It grows to 1.5 m in length.
The Diamond Trevally occurs in tropical and warm temperate marine waters of the Indo-West Pacific.
In Australia it is known from south-western Western Australia, around the tropical north of the country and south to the central coast of New South Wales.
View a map of the collecting localities of specimens in the Australian Museum Fish Collection.
The Diamond Trevally is also known as the Diamond-fish, High-brow Pennantfish, Indian Threadfish, Mirror-fish and Plumed Trevally.
The Diamond Trevally looks similar to the Pennant Fish Alectis ciliaris. It can be distinguished by the more angular shape of the head and nape versus a more rounded head, respectively. The distance between the eye and upper jaw (suborbital depth) is contained 0.8 to 1 times in the upper jaw length of the Diamond Trevally compared with 1.7 to 3 times in the Pennant Fish. There are also differences in the number of gill rakers on the lower limb of the first gill arch (21 to 26 versus 12 to 17).