If you have a pet goldfish you’ve gotten tired of, you might not want to release it into the wild. Although they’re tiny and harmless in that fish tank, letting them go can turn them into a real nuissance because they can grow to insane sizes in the wild.
We’re sure the owners had good intentions when releasing the fish. They probably thought they’d be better off in the wild, especially since all they did was swim around in a glass cube all day. But releasing them just puts a strain on the ecosystem, at least, that’s what’s happening in western Australia.
As harmless as it can seem, introducing a pet into the wild isn’t worth the risk of letting an invasive species loose on an unsuspecting ecosystem.