A lake at Dubbo’s Regional Botanic Garden will be drained to kill off a pest fish incursion.

The Eastern gambusia or mosquito fish is classed as a noxious species and has been detected in the lake in the Sensory Garden.

The Dubbo Council says it was identified in the by a fisheries officer during an informal visit.

The fish is known to compete with native species for food and resources.

They species is believed to be spread by birds, which feed on the fish and then drop them in flight or carry them through mud, stuck to their feathers and feet.

The council is allowing the lake to dry out to eradicate the adult fish and any eggs.

It will be dry for ten days before being refilled in mid-November.

The council says it then plans to introduce native fish to the lake.