Every two years NSW Fisheries and Queanbeyan Council release native fish into the river.

James Morgan, of Tackle World Fyshwick and a fisherman in local streams for more than 40 years, says many Queanbeyan children are catching Murray cod and golden perch in the Queanbeyan River.

"There's still a lot of redfin and carp, not so desired. But they provide a good food source for those Murray cod.

"Unfortunately it is outweighed by the damage the redfin do to other small fish species," Mr Morgan said.

Mr Morgan says the success of stocking is evident all along the Queanbeyan River.

"You can catch half-decent fish upstream from the [Monaro Street] bridge," he said.

Queanbeyan Council's environment education officer Jennie Wetmiller says the cod fingerlings released on Friday, February 5, were stained with a fluorochrome compound, calcein, which allows river monitors to distinguish between these and other fish not hatchery released.

"Previously we haven't had this so there was no way of doing any kind of count.

"What we see and hear from people recreational fishing, there are people fishing and catching cod within the river," Ms Wetmiller said.

The river was in good health, Ms Wetmiller said.

"One of the key indicators are platypus. If they are able to survive and flourish you know the river is doing all right."

Signs along the river bank and disposal bins will be installed to discourage people from leaving behind discarded tackle and tangled lines.

Leaving line in the water or banks can kill or injure birds, fish and platypus and pollute the water.