Auckland Council is asking locals to stop releasing goldfish and aquarium plants into waterways.
Goldfish and aquarium plants make their way into lakes and streams where they destroy the natural environment and water quality.
Peter Wilcox, who has been helping Auckland Council remove invasive fish from waterways, says goldfish that have been released into the wild are very large.
“At Western Springs, in the last catch, the smallest was 30 centimetres, the top was 40 centimetres, and they ranged in weight from just under a kilo to 1.8 kilograms.
“A goldfish that might be worth $10 in a shop becomes a thousands and thousands of dollars expense for the councils trying to manage it so they can manage the amenity for the good of the rest of the population. It’s irresponsible, it’s effectively environmental vandalism.”
Goldfish can be bought for as low as $4.50 in pet stores, however, the amount of space they require in a tank can surprise owners.
Hollywood Fish Farm Mt Roskill store owner Vicky Ferguson has seen it many times before.
“Because they’re purchased at quite a small size people think they can put a lot of them into a tank, and then they start to grow a lot bigger and outgrow the tank.”
When goldfish get into lakes and streams they rip up plants, outcompete native fish for food and stir up sediment to make the water cloudy.
Auckland Council freshwater ecologist Belinda Studholme said the fish were not the only problem, but the plants that came in tanks were an issue too.
“They totally destroy water quality, they change the dissolved oxygen and pH and the ponds. They exclude all other native vegetation and make the pond unsuitable for native fish.”
Ferguson said rather than dumping fish into waterways, owners could surrender them, or find a new home for them with somebody with a larger tank or pond in their home.
