Widespread, mostly in the northern half of Australia, from the Chapman River, NE of Geraldton, Western Australia, around the tropical north to the Genoa River, eastern Victoria, including islands in the Torres Strait, and Fraser, Moreton, Bribie and Stradbroke islands, Queensland. The species also occurs in West Papua, Indonesia, and southern Papua New Guinea.
Inhabits the lower reaches of slow-flowing coastal rivers and streams, swamps, lagoons, including the upper parts of estuaries. Empire Gudgeons prefer flowing waters, and often shelter around aquatic plants and woody debris. Juveniles frequently occur in swift-flowing waters or estuaries. The species is tolerant of high salinities, water temperatures up to 35ºC and somewhat acidic to alkaline waters with a pH 5.0-9.1.
Grows to around 12 cm SL, males slightly larger than females. Sides of body often with about 7-8 brown vertical bars, forming X-shaped marks on midside; base of caudal fin with vertically elongate dark brown spot just below midside; distinct dark mark near posterior end of the second dorsal fin. Dorsal fins with 2 black stripes; second dorsal with round white spots posteriorly, surrounded by black.