As someone who grew up in New Jersey, there were many lakes that had those little guys swimming all over the place...

And there isn't a change in hell that I would drink any of the water in those lakes. Those fish are survivors, and although I am not a scientist, I could only conclude that the fish in the lakes nearby had to have gone through some type of resistant mutation... That really doesn't help my confidence in the safety of the water.

I say use goldfish. Those little bastards take one day of me forgetting to feed them to go belly up.