The Firetail Gudgeon is a small native Australian fish that occurs in freshwater coastal streams. During the breeding season the fins of males become bright red-orange.
The Firetail Gudgeon has a compressed body, two dorsal fins and a small, oblique mouth that reaches to below the front of the eye.
The colouration of the species varies with age, habitat and season. The body is generally grey to bronze with black scale margins. During the breeding season males can be almost black, with intense red-orange fins. There is often a black bar above the pectoral fins base and a faint stripe along the side of the body.
Female Firetail Gudgeons can be easily distinguished from other species of Hypseleotris by the black area around the vent. This area is usually brown in males.