Trout cod

Trout cod have been reliably recorded to at least 80 cm and 16 kg, but there are some credible anecdotal accounts of larger specimens. Trout cod are broadly similar to the Murray cod, however there are some distinct differences in morphology and colouration. Trout cod are a small to medium groper-like fish with a deep, elongated body that is round in cross section. In contrast to Murray cod, trout cod have a pointed head with the top jaw overhanging the bottom jaw, and the slope of the head is straight. The eyes are slightly larger and more prominent than in Murray cod. The head tends to be free of speckling however a distinct dark stripe through the eye is usually present. Trout cod are cream to light grey on their ventral ("belly") surfaces. Their back and flanks are most commonly bluish-grey in colour, overlain with irregular black speckling, but this can be highly variable depending on the habitat specimens come from, and can range from almost white to light grey-green, light brown, dark brown or almost black. The black speckling on the back and flanks is consistent however. The spiny dorsal fin is moderate in height and is partially separated by a notch from the high, rounded soft dorsal fin. Soft dorsal, anal and caudal (tail) fins are all large and rounded, and are light grey to dark grey or black with distinct white edges. …

Although there is/was a very substantial overlap in range, trout cod are essentially a more specialised upland sister species to Murray cod. Therefore, the trout cod's main habitats were the larger upland rivers and creeks, which they usually co-inhabited with Macquarie perch and one or both of the blackfish species. Historical research is confirming a primarily upland distribution for trout cod; recent governmental literature lacking such historical research and suggesting trout cod are primarily a lowland fish species must be considered inaccurate. Division into specialist upland and primarily lowland species is a relatively common phenomena in native fish genera of the Murray-Darling and East Coast systems with other notable pairs shown in the following table:

Trout cod are often found close to cover and in faster currents and in cooler waters than Murray cod. Their diet is essentially the same as Murray cod with adjustment made for size, eating mainly other fishes, freshwater mussels, crustaceans, aquatic insects, small mammals and water fowl. However, recent anecdotal evidence suggests terrestrial insects made up a significant proportion of the trout cod's diet in upland rivers and streams. In the surviving Murray River population trout cod tend to stick to areas of deep water near banks, around snags, rocks or other large structure. …

Trout cod are carnivores and feed on other fish, crustaceans (such as crayfish, yabbies and freshwater shrimp) as well as aquatic and terrestrial insects. Larvae are pelagic fish and eat zooplankton.