On Tuesday, September 26, a group of people crowded around Edgewater Pond, in St. Albert, Alberta, in hazmat suits, spraying chemicals into the water. Unlike most in their position, these city staffers weren’t fighting a swamp monster, or a rogue algae bloom. They were trying to get rid of thousands of so-called “monster goldfish”: hardy, non-native fish that can grow up to a foot long and have taken over the pond. Their work continued this morning, September 28.

About four years ago, someone dropped a couple of store-bought goldfish into a stormwater pond in St. Albert. Like most who release pets into the wild, this person likely thought they were doing a good thing. Maybe the fish had a small tank, and seemed unhappy. Maybe the person was moving, and couldn’t take them along.

But as we’ve all heard, the road to hell is paved with good intentions. Similarly, the St. Albert stormwater pond is now filled with thousands of goldfish, which the city has tried to eradicate for three years straight, to no avail.

“I think of zombie movies when I think about” these fish, the city’s environmental director, Leah Kongsrude, told the CBC.

Over the years, she has led various efforts to remove them. In 2015, the department tried freezing them out, lowering the water level in hopes that the pond would ice over completely. No dice. In 2016, “we tried to electro-fish ‘em,” Kongsrude said, by zapping the water and scooping the stunned fish out. “It didn’t do anything.”

This year, the stakes are higher. Some of the fish were spotted in nearby Ted Hole Pond, indicating they had escaped their original home. “Our native fish species wouldn’t have a chance if they got out” into wild ponds or the river system, Kongsrude says.

Thus the hazmat suits and chemical spray, which only works on animals with gills. As the goldfish are the only such species in the pond, the city saw it as a way to take them out while minimizing collateral damage.

Either that, or their supervillain arc will continue, in which case these fish—which can clearly already bend ice and electricity to their will—will soon have chemical powers, too.

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