I'm a little confused, why said fish would need dirty water to feel at home, and why they are stupid. If you mean they lack intelligence then ya your right, they're only fish.
When Steven Seagal kills a ninja, he only takes its hide. When Chuck Norris kills a ninja, he uses every part.
Chuck Norris and Mr. T walked into a bar. The bar was instantly destroyed, as that level of awesome cannot be contained in one building.