DPI research leader for freshwater ecosystems, Craig Boys, said scientists at DPI’s Elizabeth Macarthur Agricultural Institute have confirmed the fish was a Central American cichlid.

“DPI fisheries scientists from Narrandera conducted a follow-up survey of Lake Albert and found no evidence of surviving Central American cichlids,” Dr Boys said. “That’s good news, but we are concerned that an aquarium, or ornamental fish, has been found in the lake.”

DPI Aquatic Biosecurity strategy leader, Melissa Walker, said ornamental fish make great pets and has reminded aquarium and pond owners that it is illegal to release them into NSW waters.

“Unwanted fish should be returned to your local pet store, given to a friend or humanely euthanised,” Ms Walker said. “Releasing ornamental fish into the wild can pose a serious threat to Australia's aquatic biodiversity through pest and disease impacts.

“Hundreds of native and exotic fish are sold by aquarium suppliers, with the ornamental fish industry estimated to be worth $350 million annually in Australia.

“It’s important to make sure fish, plants and snails in your aquarium or pond are kept clear from our oceans and waterways and be aware that heavy penalties apply to the release of these fish, plants and snails into NSW waters.

“Most aquarium species are not native to your local area or to Australia at all. Ornamental plants and animals which are accidentally or deliberately released into the wild can establish reproducing populations, which may lead to disastrous impacts on local habitats, recreational fishing and aquaculture industries.

“Once established, aquatic pests can be very difficult, if not impossible, to eradicate. To reduce the risk of pest incursions some fish species are prohibited for importation, possession and sale in NSW.”