Southern Pygmy Perch were once widely distributed throughout the Murrumbidgee and Murray River systems, as well as coastal streams in South Australia and Victoria, north-eastern Tasmania and King and Flinders Islands in Bass Strait. There have been large-scale reductions in their range since European settlement, particularly in inland regions. Populations of Southern Pygmy Perch have recently been discovered in tributaries of the upper Lachlan and upper Murray River catchments.
Southern Pygmy Perch are small fish, growing to approximately 65-85 mm in length.
They have a small mouth reaching to just below the eye, and a rounded tail. The colour varies greatly depending upon where the fish live and the environmental conditions present there. The base colour ranges from pale cream to green-brown, darker on the back and paler on the belly. There are often irregular markings on the sides, but these are also very variable; some fish may be almost plain while others have dark spots or even longitudinal bands. Breeding males display brighter colours, with the dorsal and anal fins becoming bright red with black edges, and the region around the vent and on the breast and chin turning black.