The river and banks of the Wirribi Yaluk provide an important habitat for animals including the Platypus and various species of fish and frogs. Many native freshwater fish species have been lost, but some remain. These include the River Blackfish, Trout Galaxias and Mountain Galaxias (in the river’s upper reaches) and the Australian Smelt, Common Galaxias, Congoli, Flathead Gudgeon, Pouch Lamrey and Shorthead Lamprey (in the river’s lower reaches).

Eastern Grey Kangaroos are among the many mammals that enjoy grazing on the plants that grow near the water. Others include Black Wallabies, Short-beaked Echidnas, Sugar Gliders, the Eastern False Pipistrelle and the Rakali (native water rat), which lives downstream of Melton Reservoir. Local reptiles include the Blue Tongue Lizard, Striped Legless Lizard, the Little Whip Snake, Eastern Brown and Tiger Snake. The Wirribi Yaluk is also home to 11 frog species. Two of these, the Growling Grass Frog and Bibron’s Toadlet, are threatened.