"If you have a goldfish, and you are kind of over that goldfish, to the point where you are now wondering whether it might be best to set that goldfish free, please rethink that decision."
"That's the request from the Alberta government, which is trying to get Canadians to refrain from dumping out their fish tanks into ponds. Because those ponds are filling up with those discarded goldfish, which are getting really, really big in the wild."
"'It's quite a surprise how large we're finding them and the sheer number,' Kate Wilson, aquatic invasive species coordinator at Alberta Environment and Parks, told the broadcaster."
"In one case, the municipality of Wood Buffalo pulled 40 of the domestic fish species from a stormwater pond."
"'That's really scary because it means they're reproducing in the wild, they are getting quite large and they are surviving the winters that far north,' said Wilson."
From the http://ow.ly/OQana:
Discarded pet goldfish are multiplying and getting kind of ginormous, officials say
So if you could not dump your aquariums in lakes or otherwise dispose of your fish in an improper manner, that would be super.