Native fish populations could be at risk, with an exotic fish species on the loose in a number of rivers in northern New South Wales.
Jane Frances, NSW Department of Primary Industries (DPI) Aquatic Biosecurity and Risk Management manager, said: “NSW DPI has a slippery job on its hands, and is asking fishers and swimmers in the area around Murwillumbah and Uki to keep a lookout for the fish, known as the Pearl Cichlid or Pearl Eartheater, a native of South America.
“Some of the cichlids were discovered in pools below Clarie Hall Dam, on a tributary of the Tweed River, by a fisherman.
“The species is a popular aquarium fish, having an attractive pattern of pearly spots over a grey-green body with red or red-edged fins.
“They may look nice in an aquarium, but in the wild, these fish can become an established pest, impacting on native fish populations.
“NSW DPI was preparing an eradication attempt when it came to light that the same species of cichlid had also been seen in the Oxley River many kilometres upstream.
“The Department is trying to determine exactly how widespread the fish have become.”
The Department’s job is made more difficult because the fish can be very elusive, often difficult to see and even harder to catch.
“Normally we search for fish using traps and electrofishing, where an electric current temporarily stuns the fish and allows us to catch and count them,” Ms Frances said.
“Although our researchers saw a few of these cichlids in the water, they were only able to catch one.
“For this reason, the Department is now appealing to the public for help in its search.
“If anyone has any information about the whereabouts of this fish in northern NSW rivers, we would really appreciate a call on 1300 550 474.
“If you catch one while fishing, the best thing is to freeze it and record exactly where you caught it, then call the NSW DPI to arrange for the fish to be positively identified.”
The Department is concerned what impacts the pearl cichlid may have if it becomes widespread in the river system.
It is an extremely hardy fish, being able to survive in water temperatures down to around 10°C, despite being a tropical species, and in full-strength seawater, despite normally living in fresh water.
When breeding, a pair cleans a nesting site and guards the eggs, and may be very aggressive to other fish which enter their territory.
“This is another example of a new potential pest entering our waterways and threatening the local aquatic life through the careless actions of one or two people,” Ms Frances said.
“Aquarium fish only belong at home in a fish tank. If you have unwanted fish, take them back to a pet shop, give them to a friend or dispose of them in a humane way. Never, ever dump pet fish into the wild.”
To report sightings of the pest fish, call the NSW DPI on 1300 550 474.