I have two different style (commercially made) rain barrels which I
use primarily for watering my vegetable garden. It has become very apparent that the screening on top is not enough to keep mosquitos from breeding.
I did a little searching and goldfish were recommended. I think this would be a dismal existance for a fish and don't even want to think about the water getting low, winter coming, etc.
I do not want to use chemicals since I garden organically.
At this point I have poured several cups of vegetable oil in each with the hope that it will float on top and inhibit the mosquitos. So far it has seemed to be working.
Any thoughts or advice?