Gold fish and Koi can be beautiful to look at but only in the right places.

And storm ponds are not the right place for them, but that's where a lot of them are apparently turning up in High River.

Mayor Craig Snodgrass says it needs to stop because they grow and reproduce in the ponds.

"The issue is they will grow and they will breed in there and the problem compounds itself with the waste they produce, just increases algae growth and it can go just out of control on you," he says. "What we have to do immediately is get rid of these gold fish, we've got to kill them and get them out of there somehow, we don't like doing that, we shouldn't have to do that."

He says the fish could even end up in the Highwood river and end up choking the river with algae and eventually killing it.

"Once they're in that pond, and if they migrate into the Highwood River, now we've got a massive, massive issue because they can destroy that river very easily," Snodgrass says. "They've already got a big problem with it in Calgary that they're trying to get the population educated to not do this."

He says people who do it to "set the fish free" are not helping the fish and not helping the storm-pond system.