AFTER discovering one of the world's most invasive fish in the Condamine River, the Department of Agriculture, Fisheries and Forestry came back this week in search of more pearl cichlid.

To the delight of the department and the Warwick Fish Stocking group, no more were discovered.

The lone pearl cichlid was discovered near the Grafton St Bridge earlier this month.

Warwick Fish Stocking Group member Ed Kemp said it was a relief the department didn't detect any more of the dreaded fish.

"No one came forward to tell us how many could have been in the river," Mr Kemp said.

"The department saw it as top priority to come back and check the river again.

"It would have been a real disaster if they found more, but thankfully it seemed to be alone."

Condamine Alliance river manager Kevin Graham said the pearl cichlid were popular aquarium fish.

"Native to South America, this fish, when released in the wild, can potentially become a significant pest, based on their size, hardiness and aggressive behaviour," Mr Graham said.

"The monitoring program is primarily focused on tilapia as part of a broader tilapia exclusion strategy project to help keep tilapia out of the Murray-Darling Basin.

"Whilst we are lucky that so far it is only one fish, and it isn't a tilapia, it does highlight that we do need to remain vigilant. Our rivers are only for our native fish."

Pearl cichlids have been found over the Great Dividing Range, but to date it was the first official sighting in the Murray-Darling Basin.

Cr Neil Meiklejohn joined the Fish Stocking Group at the river on Tuesday to discuss future plans involving council.

Cr Meiklejohn explained why some sections of the riverbanks were mowed and others were let grow.

"The weeds on the side of the river provide the fish with food and give them somewhere to live," he said.

"While we understand residents want to fish on the side of the river there has to be a balance. The fish habitat needs to be protected."

Deadly fish

How to identify them: The dorsal (upper) fin is continuous and ends in an extended point.

Most native fish have a dorsal fin with a dent or gap in the middle and a rounded end.

The two pelvic (belly) fins are long and almost touch the front of the anal (bottom) fin, whereas most natives have short pelvic fins.

Never throw tilapia back into a waterway, don't use tilapia as bait (dead or alive) and don't stock dams or ponds with tilapia.

Native fish include: Murray cod and golden and silver perch.