About This Fish

Threadfin Salmon


The threadfin salmon (Polydactylus macrochir) is also known as King Threadfin Salmon, King Salmon and Burnett River Salmon. It belongs to the family Polynemidae under order Perciformes of class Actinopterygii. It is found mostly in very shallow water along the coast, in muddy bays, estuaries and rivers of tropical Australia from Fraser Island to west of Darwin and occasionally in freshwater. It is a bottom-dwelling fish with elongated body and inferior mouth.



The threadfin's body has no spots or stripes. Back is bluish-silver and belly is whitish in color. Dorsal, anal and caudal fins are blackish while pectoral, pelvic fin and pectoral filaments are whitish or yellow in color. It has a deeply forked tail and two fairly large dorsal fins of approximately equal size. Second spine of dorsal fin is more robust than the rest. A large gap is present between Spinous and soft dorsal fins. The single anal fin is similar in size and shape to the second dorsal fin. Posterior margin of maxilla extends considerably beyond level of posterior margin of adipose eyelid. Pectoral fin has 2 sections, of which, the upper section of pectoral fin contains unbranched rays while the lower section with 5 long free rays. Pelvic fin is subabdominal with one spine and 5 soft rays. Lateral line is complete which runs from the upper edge of the gill cover to the base of the caudal fin. It mainly eats seasonally abundant prawns, small fish and other small crustaceans. Spawning occurs from October to early March. It grows up to 170 cm in length and 45 kg in weight. It can live up to 20 years.


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Location Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Southern Australia
Western Australia