It may seem harmless, but this little goldfish can have a big impact on the ecosystem. (iStock/Laures)

We know invasive species can be a real issue for local ecosystems, but did you ever think that one of the most common pets across North America could be the culprit?

If you've ever thought about putting your goldfish back in its wild home, or flushing it down a porcelain path, officials in Canada have a message for you: you may think it's humane, but it's actually detrimental for the environment.

"This practice is very harmful to native species, to Alberta waters, to our biodiversity and the fish that actually belong here," Kate Wilson, an aquatic invasive species specialist with Alberta Environment and Parks, told CBC News.

These goldfish have become a real issue in Edgewater Pond in St. Albert, where droves of goldfish have been taking over the ecosystem since last summer. In Minnesota, officials warned that goldfish showing up in lakes there were found as large as the size of dinner plates.

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According to Ontario's Invading Species Awareness Program, goldfish reduce biodiversity by competing with native species and becoming a main predator of a variety of flora and fauna.

"They stir up mud and other matter when they feed, which increases the cloudiness of the water and affects the growth of aquatic plants," their website reads.

On top of that, they can reproduce quickly and are often very difficult to catch and kill. Officials tried electro-fishing them and even drained the pond, the St. Albert Gazette reports, but the fish survived even through the frigid Canadian winter.

"Unfortunately with the winter we've had, we weren't able to get full freezing so the ice wasn't quite as thick," Sarah Cicchini, St. Albert environment coordinator, told Global News.

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Spring has brought a sobering realization for wildlife officials: the goldfish are still there, and they're thriving.

This wouldn't be a major concern if the problem was contained within the storm water pond, but officials are looking to see if the fish can be found in other ponds, Tech Times reports, and there's no way to prevent the fish from making their way into the streams and lakes in the larger ecosystem.

Flushing is just as bad, even if you are certain your fish is dead.

"Even if the fish are dead, they could have diseases or parasites that could be introduced,"Wilson told Fort McMurray Today,"especially if the water treatment system is not top notch."

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