The fifty-four specimens of fishes brought back by the Australian Museum Expedition belong to eight families or ten species of shore-inhabiting kinds such as are found in tropical mangrove-swamps or else in freshwater rivers. There are no coral reef or open marine forms because the main activities of the expedition were concerned with geology and terrestrial fauna. The Palmer or "Barramundi", Lates calcarifer (Bloch, 1790), was photographed at the Forrest River (Keast, Austn. Mus. Mag., xi, 1953, pp. 4, 9–10, fig.) but no specimen was preserved.
In the interior of Australia, drought conditions were encountered, so specimens could only be obtained from three localities: Wilson River and Forrest River in the Kimberley Division of Western Australia and at Port Keats in the Northern Territory. Previously the Australian :Museum had no fishes from any of these places, so they are of zoogeographical interest. The range of several freshwater fishes (chanda perch, and gudgeon) and of two estuarine mudskippers can be extended into Western Australia for the first time as a result of this expedition's work. The freshwater fishes all belong to the Leichhardtian fluvifaunula which embraces the rivers of southern New Guinea and Papua, north-western Queensland, the Northern Territory and north-western Australia, which seem to share the same species of fishes and other aquatic animals.