An 11-year-old St. Albert boy and his grandfather are sharing their story, after they caught a record-breaking koi in an area lake, days before officials were to cull the invasive fish from that very body of water.

Luke Hebb and his grandfather Bob Aloisio were fishing in Lacombe Lake Wednesday, when Luke got a big bite on his line.

“He just handed me the rod and he jumped in,” Aloisio said.

“For a moment the koi was winning, but then I got ahold of it and I chucked it onto the side,” Luke said. He told CTV News he thought the fish would be about 10 pounds, but it actually weighed in at 16 pounds and measured 30 inches long.

At the same time, St. Albert environmental scientist Melissa Logan was collecting a water sample nearby.

“I came over and indeed he had caught the biggest koi I had ever seen,” Logan said. “And he caught it with hot dogs.”

It turns out, the fish was the largest koi ever reported in the province. Logan said the presence of such fish is a problem.

“It’s a nice fish, but it’s an invasive species,” Logan said. “They will out-compete the native fish.”

Goldfish and koi are usually found at a pet stores and remain small if they are kept in a fish tank or small pond. In open water, they can grow exponentially and pose a threat to native fish populations.

One year ago, crews removed thousands of invasive goldfish from a St. Albert pond and next week, crews are hoping for similar results when they start to cull the goldfish population in Lacombe Lake.

“They can freeze, and then actually thaw in the spring and keep on swimming,” Logan said. “This is our last resort.”

Between September 4 and October 2, crews will work to remove the invasive fish species from Lacombe Lake.

Crews will treat the lake using a chemical called Rotenone, a natural compound derived from the roots of a tropical plant. The treatment is commonly used to eradicate invasive fish populations; officials said it is not harmful to humans, pets, wildlife or vegetation, and breaks down naturally after it is used.

Back in September 2017, crews pulled 45,000 goldfish from the Edgewater and Ted Hole storm water ponds.

With files from Jeremy Thompson