Oriental weatherloach escaped from aquariums in the early 1980s and has now invaded NSW, Queensland and Victorian waterways.

NSW Department of Primary Industries conservation management officer, James Sakker, said the feral fish had colonised many NSW waterways including the Murrumbidgee River, Lake Burrinjuck, the Shoalhaven River, the Murray River, Warragamba Dam and Lake Eucumbene and their tributaries.

“It is a threat to the environment in these areas because it can out-compete native fish for space and food and may eat the eggs of native species,” Mr Sakker said.

“It is possible for one female to lay up to 100,000 eggs in her lifetime and due to its hardiness and mobility there is a high risk of the weatherloach establishing in new areas.

“This fish is a real survivor – it can tolerate temperatures between two degrees C and 30 degrees C and can take in air to its modified gut when dissolved oxygen levels in the water fall,” he said.

Mr Sakker described the fish as eel-shaped, almost cylindrical and up to 20 centimetres long with five pairs of whiskers around the mouth.

“It is usually mottled brown or yellow with many tiny black spots and a white belly.”

Mr Sakker warned that the fish could be illegally spread by anglers using it as live bait.

“The use of any live fin fish as bait is prohibited in NSW rivers and dams and heavy penalties apply,” he said.

“Aquarium fish should never be released into our waterways.”

To help NSW DPI combat pest fish join the Threatened, Protected and Pest Fish Sighting Program or report sightings on line to www.fisheries.nsw.gov.au/threatened_species, email aquatic.pests@dpi.nsw.gov.au or phone the 24 hour recorded hotline on (02) 4916 3877.

To join the program contact Bill Bardsley or James Sakker on (02) 4982 1232.

This story appears Agriculture Today.