The river blackfish (Gadopsis marmoratus) is a freshwater fish endemic to the temperate waters of south-eastern Australia. It is found from southern Queensland through to central Victoria, including in the Murray-Darling river system. It is also found in some eastern and southern flowing coastal rivers. Found primarily in upland and midland habitats, though early records of fish fauna suggest it was originally far more extensively distributed and was found in some lowland habitats as well. Originally, river blackfish co-inhabited many of its lowland and midland habitats with species such as Murray cod and golden perch, and its upland habitats with species such as trout cod and Macquarie perch. It is a popular angling fish in some parts of its range. Description River blackfish are elongated with a rounded body, distinct snout and large mouth, and small to moderate sized eyes. The caudal fin, soft dorsal fin and anal fin are rounded. The spiny dorsal fin is low, weak and blends into the soft dorsal fin. Colour varies but is usually either yellow or green with dark green mottling, or a very dark purple/black colour. It is an ambush predator that takes crayfish, shrimp, small fish and aquatic insects. It is strongly nocturnal. Murray-Darling river blackfish show a maximum size of around 30 cm and < 0.8 kg, with larger specimens from coastal drainages reaching up to 60 cm (Gellibrand River). It is a highly underrated sportsfish, particularly the Southern form. It is fast and strong, and has been shown to take flies and lures, even surface lures, in addition to the more usual worm baits. There is an unofficial world record caught by Piotr Pomorski on a WildBait Lure, in Victoria Australia that measured 70 cm in length.
