I've been having a really bad mosquito problem every year since I started collecting rain water in a 55g plastic water barrel. I've tried sealing it but they still get at the water somehow. Then I started thinking. Could feeder comets (goldfish) live in the barrel during the summer months? I don't see what not. Its not to cold and they could live primarily on mosquito larva and algae. The water changes happen automatically to. 
What do you think?

What do you think?