A comparatively large fish growing up to 35cm long in this region (up to 60cm in Victoria). It was once common throughout the Murray Darling Basin and the Gulf streams (in particular River Torrens and the Onkaparinga River). The distribution of this species has been severely restricted throughout its former range. It is now thought to be extinct in the Gulf streams (nevertheless, this quite elusive and nocturnal species may still be found somewhere in the Gulf streams). It can still be found in some watercourses of the Adelaide Hills which flow into the River Murray around Lake Alexandrina (Angas River and Tookayerta Creek).

This species can be found in a wide range of stream habitats, from fast moving, clear and cooler mountain streams and medium sized Rivers. However, it is only found in water where abundant cover such as snags, boulders and hollow logs exist. Is known to spawn in hollow logs, integrity of habitat is crucial to the long-term survival of this species. Life cycle is completed entirely in freshwater.

The River blackfish is susceptible to increased sediment loads in its habitat. The freshly laid eggs will quickly die following being smothered by a thin layer of silt. Furthermore, such sedimentation increases the mortality rates of juvenile fish. Inappropriate agricultural landuses resulting in excessive run off and weir desilting operations are largely implicated in the increase of sedimentation in streams and rivers.