This invasive species may finally be sleeping with the fishes.
The third time appears to be the charm for determined officials on one Canadian city who waged war again this week against thousands of foot-long, seemingly indestructible “monster” goldfish threatening a river’s ecosystem.
For the past three years, St. Albert has tried to wipe out the giant Asian goldfish in 2015 by freezing them, and when that failed, by electrocuting them in 2016.
The shock treatment didn’t work either, so on Tuesday, officials sprayed the pond with chemicals that target animals with gills.
As of Wednesday morning, around 4,000 dead goldfish had been pulled from Edgewater pond, and officials said they planned to attack them again with the rotenone – to make sure the scaly critters stay dead, CTV News reported.
The “extremely aggressive” fish were introduced by people who probably thought they were getting rid of their pets humanely by releasing them into a storm water pond, according to Leah Kongsrude, St. Albert’s environment director.
“They’re really cute little goldfish in your little glass bowl, but you let them out and they turn into monsters,” Kongsrude told Metro News Canada. “I call them franken-fish.”
The goldfish, which continued growing because they were no longer confined to tiny bowls, took over two storm water facilities, and threatened to outcompete native species if they spread to the Sturgeon River.
“They’re very resilient, very tough and our native fish species wouldn’t have a chance if they got out there,” Kongsrude told the CBC.
This article originally appeared on the New York Post.