Animal Species:River Blackfish, Gadopsis marmoratus (Richardson 1848)
The River Blackfish occurs in freshwater streams of south-eastern Australia. It has a reduced distribution because of habitat degradation but is common in some areas.
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 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 60 cm in length, but individuals this size are uncommon. It is usually seen at sizes up to 45 cm.
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.
The River Blackfish occurs in south-eastern Australia.
The map below shows the Australian distribution of the species based on public sightings and specimens in Australian Museums. Source: Atlas of Living Australia.
Distribution by collection data
The species occurs in freshwater streams, but has a reduced distribution because of habitat degradation. It is still common in some areas.
In New South Wales and the Australian Capital Territory, the 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.
Feeding and Diet
It eats insects, crustacea and sometimes other fishes.
Other behaviours and adaptations
The River Blackfish is a nocturnal species.
- 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.
Mark McGrouther , Collection Manager, Ichthyology
Tags fishes, ichthyology, River Blackfish, Gadopsis marmoratus, Percichthyidae, freshwater, pale green, yellowish, brown, black, marbled pattern, dark blotches, blotches/mottled, pale underside, 30 cm - 1 m,