Polydactylus sexfilis (Valenciennes, 1831)
Sixfinger threadfin
Polydactylus sexfilis
photo by Randall, J.E.

Family:  Polynemidae (Threadfins)
Max. size:  61 cm TL (male/unsexed); max.weight: 3,170.0 g
Environment:  reef-associated; freshwater; brackish; marine; depth range 1 - 50 m
Distribution:  Indo-Pacific: mainly around oceanic islands. Known from Mauritius, Seychelles, Kenya and many islands of the northern Indian Ocean; then from Indonesia north to the Ryukyu, Ogasawara and Yaeyama islands and east to the Hawaiian Islands, French Polynesia and Pitcairn. Has not been collected in Australia (Ref. 57343).
Diagnosis:  Dorsal spines (total): 9-9; Dorsal soft rays (total): 13-13; Anal spines: 3-3; Anal soft rays: 11-11. Body uniformly golden silver; occasionally with several faint dark stripes along longitudinal scale rows above and below lateral line. Pectoral filaments 6 with tip of uppermost filament reaching to or slightly beyond level of posterior tip of upper part of pectoral fin (Ref. 41110).
Biology:  This schooling species occurs along sandy and rocky shorelines and over sandy lagoon bottoms, often in zones of turbulence (Ref. 9685). Benthopelagic (Ref. 58302). Often encountered in river mouths or brackish mangrove estuaries. Feeds mainly on crustaceans (shrimps and crabs), polychaete worms, other benthic invertebrates; also on teleosts (Ref. 9685). A lunar spawning rhythm occurs close to shore (Ref. 9685). Sexual maturity in males occurs at 12 to 15 cm (Ref. 9685). Subsequently undergoes sex reversal passing through a hermaphroditic stage, and become female between 18 and 24 cm (Ref. 9685). The potential of this species for aquaculture has been studied (Ref. 9685).
IUCN Red List Status: Not Evaluated (N.E.) Ref. (126983)
Threat to humans:  harmless
Country info:   

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