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River Blackfish
Gadopsis marmoratus Richardson 1848
A 110mm long River Blackfish from the Namoi River drainage, New South Wales, March, 1998 (AMS I.38753-002). View larger image.
The River Blackfish may be pale green, yellowish, brown or black in colour. It usually has a marbled pattern with larger dark blotches. The underside is pale yellow, blue or purple-grey. The upper jaw is longer than the lower.
The pelvic fins of this species are positioned under the opercular openings. Both pelvic fins consist of a single branched ray. The spinous portion of the dorsal fin is lower than the soft-rayed portion.
The River Blackfish grows to 600mm in length, but individuals this size are uncommon. It is usually seen at sizes up to 450mm.
It is a nocturnal species that eats insects, crustacea and sometimes other fishes.
The River Blackfish, found in freshwater streams in south-eastern Australia, has a reduced distribution because of habitat degradation. However, it is still common in some areas.
In New South Wales and the Australian Capital Territory, this species is mostly found in westerly flowing streams. In South Australia it is restricted to an area in the south east of the state. It occurs widely in Victoria, and is found in northern and southern Tasmania.
View a map of the collecting localities of specimens in the Australian Museum Fish Collection.
A second species in the genus Gadopsis, is also found in freshwater streams of south-eastern Australia. The Two-spined Blackfish, G.bispinosus Sanger 1984 has a more restricted distribution. This species has only two spines in the dorsal fin, while the River Blackfish has 6 to 13.
Further reading
- Allen, G.R. 1989. Freshwater Fishes of Australia. T.F.H. Publications. Pp. 240.
- Jackson, P.D, Koehn, J.D., Lintermans, M & A.C. Sanger. in McDowall, R.M. 1996. Freshwater Fishes of South-Eastern Australia. Reed Books. Pp. 247.
- Merrick, J.R. & G.E. Schmida. 1984. Australian Freshwater Fishes. Biology and Management. John R. Merrick. Pp. 409.
