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.

River Blackfish, Gadopsis marmoratus

Carl Bento © Australian Museum

Standard Common Name

River Blackfish

Identification

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.

Size range

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.

Similar Species

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.

Distribution

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.

Gadopsis marmoratus

Distribution by collection data

Ozcam map of River Blackfish specimens in the Australian Museums.

What does this mean?

Habitat

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.

Classification

Species:
marmoratus
Genus:
Gadopsis
Family:
Percichthyidae
Order:
Perciformes
Class:
Actinopterygii
Subphylum:
Vertebrata
Phylum:
Chordata
Kingdom:
Animalia

What does this mean?

References

  1. Allen, G.R. 1989. Freshwater Fishes of Australia. T.F.H. Publications. Pp. 240.
  2. 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.
  3. Merrick, J.R. & G.E. Schmida. 1984. Australian Freshwater Fishes. Biology and Management. John R. Merrick. Pp. 409.


Mark McGrouther , Collection Manager, Ichthyology
Last Updated:

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,