"The Barraway differs from other native carp gudgeons because it has distinct vertical bars on the body and the dorsal fins have horizontal stripes of light blue, black and red," said Helen Larson from the Museum of Art Gallery in the Northern Territory.

"In addition the caudal fin has several dusky bars, or row of spots, and a dark bar on the pectoral base," said Larson.

The fish, which has only been found in the upper reaches of the Katherine River in the Northern Territory, was probably washed into the uranium pit during monsoon rains.

"They seem to have a preference for clear quiet water with shelter provided from steep banks and overhanging trees," said Larson.

A breeding programme has begun to ensure the survival of the small, fat fish, which grows to the size of a human's thumb.

"The Barraway is small, rare and quite an attractive fish, making it an interesting addition for aquariums," said local fish breeder Dave Wilson.

"They are actually quite difficult to breed in captivity as the larvae need a particular type of movement to excite them into eating. The breeding program will help ensure the species is protected and will also provide an income for the traditional (aboriginal) owners."

(Reporting by Michael Perry; Editing by Sanjeev Miglani)