reptiles

Kate Brady/Flickr

The aquarium needs cleaning and the kids have lost interest in the fish.  Or the frogs. Or the gecko. 

But flushing or dumping everything outside is a bad idea for two reasons:  one, it's inhumane for the animals and two, it's a really bad idea for the environment.

The same hardiness that makes milfoil and goldfish such great aquarium dwellers means they also excel as  invasive species.