Pi 290 Alectis indica
Phylum: Chordata
Class: Actinopterygii
Order: Carangiformes
Family: Carangidae
Genus: Alectis
Species: Alectis indica
Description
The Indian
threadfish (Alectis indica), also known as the Indian
threadfin, diamond trevally, mirror fish or plumed
trevally, is a large species of coastal marine fish of the jack
family, Carangidae. The
Indian threadfish has the typical body structure of a large jack, with a
distinctly angular, strongly compressed body. The major identifying feature of
the species is its head profile, having a slight concavity near the eyes which
distinguishes it from its close relatives in the genus Alectis. The dorsal
profile of the fish is more curved than the ventral profile, and the body is
deepest between the origins of the soft dorsal and soft anal fins. The first section of the dorsal fin consists
of 5 to 7 visible spines, with the second section having one spine and 18 or 19
soft rays. The anal fin has two spines followed by a single spine and 15 or 16
soft rays. The pectoral fin is long and curved, extending beyond the junction
of the straight and curved sections of the lateral line. The body appears to be
scaleless, but on closer inspection has minute, deeply embedded scales. The
lateral line is strongly curved anteriorly, with a section of 6 to 11 scutes
toward the tail. Juveniles have long, filamentous trailing anal and dorsal fin
spines, much like those of Alectis ciliaris. The species is known to grow to
165 cm and 25 kg. The body of adults is a silvery blue-green colour above,
being darkest on the head and silver below. The upper operculum has a small
diffuse dark spot. The long filamentous soft dorsal and anal fins as well as
the pelvic fin are a dark blue to black colour, while the others are pale green
to hyaline in appearance. Juveniles have 5 to 7 broad dark vertical cross bands
through their body.
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