Gadopsis

Gadopsis is a genus of freshwater cod endemic to southeastern Australia. The genus currently contains two recognized species:

• Gadopsis bispinosus (Two-spined blackfish)
• Gadopsis marmoratus (River blackfish)

These fish are members of the family Percichthyidae (temperate perches). They are characterized by elongated bodies, a single dorsal fin, and the absence of an adipose fin. Gadopsis species are benthic, typically inhabiting rivers and streams with rocky or woody debris that provide shelter. They are carnivorous, feeding primarily on aquatic invertebrates.

Both species within the Gadopsis genus are facing conservation challenges due to habitat degradation, introduced species, and altered flow regimes in their native waterways. Populations of both G. bispinosus and G. marmoratus have declined significantly in many areas. Conservation efforts are underway to protect and restore their habitat, and to manage the threats they face.

The River blackfish, Gadopsis marmoratus, is the larger and more widely distributed of the two species. The Two-spined blackfish, Gadopsis bispinosus, is found in more restricted areas, mainly within Tasmania and a limited area in Victoria. The distinguishing feature between the two species, as indicated by the name of G. bispinosus, is the presence of two spines on the operculum (gill cover), while G. marmoratus typically has only one. However, this is not always a reliable characteristic. Careful examination of other morphological characteristics and geographic location is important for accurate species identification.