Pet goldfish are a staple of childhood, but many of these poor fishies don’t last long in their little fishy bowls, and the next stop always seems to be the toilet. It may seem like the best option — the toilet leads back to the open water, where fish belong, right? Just like in Finding Nemo.

But nah. It’s a very bad idea to flush goldfish down the toilet, particularly if they’re still alive.

Photo Credit: iStock

Because people flush their goldfish so often, there are now tens of millions of goldfish in areas where they are not native, such as the Great Lakes. They have no natural predators there, so they can live longer and grow way larger than the fish you’re used to seeing in the pet store.

Buffalo Niagara Waterkeeper, a New York-based water protection agency, shared one photo of an absurdly large goldfish to really drive this point home. This fish is 14 inches long.

This is why you should never flush your fish! This 14-inch goldfish was caught in the Niagara River, just downstream of…

Posted by Buffalo Niagara Waterkeeper on Friday, June 14, 2019

This oversized goldfish was caught in the Niagara River after being flushed or released.

So, why are all these giant goldfish a problem? They’re an invasive species in North America, and they’re able to out-compete native species of wildlife.

“Without a natural predator, they’re winning all the competition for food and resources,” Jennifer Fee, marketing director at Buffalo Niagara Waterkeeper, told HuffPost. “They’re winning, they’re lasting longer and they’re continuing to live and grow.”

So, if you find yourself with a live goldfish that you can no longer keep, do the Earth a favor and take it back to the pet store instead of dumping it in the toilet.