Garden waterfall and mosqitos.

[huahin4ever]

I have a small fountain/waterfall in my garden. The pump is installed in the bottom of the pond, so the water is generally not flowing very much, and most of the time I keep it switched off. I'm worried the water could be stagnant enough for mosqitos to breed. If that's the case are there any chemical(s) I could add to the water to prevent this from happening? I'd like to avoid draining the whole waterfall just because it's off most of the time. The chemical must of course be color less and not damage the pipes/pump.

[Roel]

If possible put in some of these little fish. They feed on mosquito larvae. That is why many Thais have these fish bowls in front of their houses. Not only decoration. Serves a purpose to.