‘Any species can be a problem, but carp and goldfish will stir up and disturb the rivers’ bottoms, destroying the environment for native species,’ Fisheries biosecurity team leader Victoria Aitken said.
Current threats include tilapia fish from tropical tanks, mystery and apple snails left in tank gravel dumped near waterways and the pest pearl cichlid fish in Bennett Brook in Caversham that can survive in the salty conditions of the nearby Swan River.
‘Cichlids may need one place to breed, but they can live and compete with native species in a wide range of places,’ Ms Aitken said.
To combat the threats, Fisheries and the aquarium industry have launched a campaign of posters and information stickers at pet shops on how to properly dispose of any unwanted species.
Ms Aitken said no fish, snail or plant from tanks should be put in waterways, toilets, drains or the ocean.
‘If fish owners no longer want their fish, they are encouraged to give them to other responsible fish owners or an organisation with an aquarium, or to seek advice from their local pet shop,’ she said.
– Disposal advice is at www.fish.wa.gov.au /biosecurity and pest sightings should be reported to Fishwatch on 1800 815 507.