; subclass Actinopterygii, order Perciformes)
A monospecific family (Gadopsis marmoratus, river blackfish), which is endemic to south-eastern Australia. A fairly slender fish, it has a long, low dorsal fin and an anal fin partly enveloped by thick skin. The pectoral fins each consist of a single divided ray, and the tail fin is rounded. Found in fresh water only, it grows to 60 cm.
Subjects: Zoology and Animal Sciences.