Since pulling 882 goldfish out of Anders Pond in 2019, City of Red Deer staff have not formally studied the invasive species situation in other city ponds.
But Geoff Stewardson, wastewater superintendent, said parks and environmental services workers will be keeping a lookout for non-native fish species while doing other work around these waterways this spring and summer.
And he encourages Red Deerians to report any sightings of goldfish or any other species that should not be in local retention ponds.
If an invasive fish is reported on the city’s Report a Problem line, city staff will be sent to the pond to investigate, he added.
Some of the city’s retention ponds provide indirect access to the Red Deer River — which was already found to contain carp, another prolific and highly invasive type of non-native fish.
Goldfish are part of the carp family. If born in open waters, goldfish tend to grow in size and change to a duller colour to fit with the environment, so they are harder to spot, added Stewardson.
According to the provincial government’s website, Alberta has more than 50 populations of goldfish that are thriving in the wild, as far north as Fort McMurray.
Released aquarium pets have been known to lurk in Red Deer’s stormwater ponds where they have rapidly reproduced – 882 of these fish were removed from Anders Pond at a cost of $250,000 in 2019-20.
Since then, the city has assessed how it would handle another proliferation of aquarium species in the water system, since the fish removal was expensive with a chemical process that has no effect on fish eggs.
“All the costs would be undone if somebody put another goldfish in the pond,” a city manager previously observed.
West Park Pond had been next on the list for goldfish removal in 2020, but municipal workers had first wanted to evaluate the success of the Anders program.
Stewardson said, to his knowledge, there’s been no re-occurrence of goldfish in the Anders pond, and he’s heard of no goldfish complaints in the West Park pond.