Thousands of years of droughts and floods have shaped the evolution of native fish in the Murray-Darling Basin. From clear, fast-flowing, rocky-bottomed streams to turbid, meandering slow-flowing rivers and chains of waterholes, our native fish have adapted to a great diversity of habitats and conditions. There are 46 native fish species in the Murray-Darling Basin, from small-bodied gudgeons that may reach only 5 cm through to the iconic Murray cod that has been recorded as long as 1.8m.
Major fish habitat in upland rivers and streams is typically provided by small pebbles, rocks, bedrock and riparian vegetation. Rocks provide shelter and a potential food source for fish as many different types of aquatic algae and macroinvertebrates also call the rocks home. Riparian vegetation provides much of the food for native fish. In contrast to the slow flows and waterholes that fish use in lowland systems, stream habitat in upland systems is characterised by how water travels along river beds—riffles, pools and runs.
Lowland riversystems are often the life blood for networks of extensive floodplains which contain billabongs, wetlands and river redgum forests. Floods connect the floodplains and billabongs to the river systems periodically and provide opportunities for native fish and many other aquatic species to breed and move throughout the landscape.
Fallen trees and logs (or snags) provide habitat, breeding areas as well as food for native fish. Snags also encourage waterholes to be scoured out during floods providing refuges for fish, aquatic vegetation and macroinvertebrates.
“Information on the identification and ecology of all native fish in the Basin can be found in Fishes of the Murray-Darling Basin: An introductory Guide. The individual fact sheets listed below provide information to help people identify most of the native fishes found in the Basin”.
Darling River hardyhead
Dwarf Flat-Headed gudgeon
Northern river blackfish
Southern purple-spotted gudgeon
Southern pygmy perch
Western blue-spot goby
Yarra pygmy perch
Allen, G.R, Midgley, S.H. and Allen, M. (2002). Field Guide to the Freshwater Fishes of Australia. CSIRO Publishing, Melbourne./
Humphries, P. and Walker, K. (eds.)(2013). Ecology of Australian Freshwater Fishes. CSIRO Publishing, Victoria.
Merrick, J.R. and Schmida, G.E. (1984). Australian Freshwater Fishes: Biology and Management, Griffith Press, Netley.