Organic water treatment to kill mosquito larvae?

I live in proximity to a 20' x 20' x 2' to 4' pool of standing water on tar that I can not remove, but I could treat if I am fairly discreet about it.

I want to prevent it from becoming a mosquito factory.

What's a good, non-toxic treatment that would serve this purpose, but not harm any birds that might find it attractive?

A few 15-cent goldfish will take care of the mosquito larva. Rosy red minnows will clear up the larva too. Dunks work too, although these are a bit more expensive. I guess if you added fish, someone will know they were added by someone, but so what?

You could try mosquito 'dunks', doughnut shaped discs containing a variety of Bt that kills the larvae but is not toxic to birds or mammals. A good garden center would stock them, or you can do a search and order online.

Sue

Zone 6, south-central PA

How is this possible? Is it a shaded section of parking lot with one helluva sinkhole? Many cities around here have regulations against standing water [West Nile virus has put a scare into them] - maybe yours does too? There are mosquito treatments for standing water - ask at your local nursery.

You might just use a couple tablespoons of olive oil.

If the pond dries up by mid-summer, it might be better in the long run to install a bat house. There's a plan at this site.

A more-or-less flat roof with bad drainage that's in shade about half the day.

As it belongs to my landlord, and the only people who could know it exists are his tenants or employees, I prefer to take a non-confrontational approach to preventing problems associated with it.

Besides, my cats enjoy watching the birds that visit the water hole.

Thanks to all for the suggestions; I think the mosquito dunks are probably the best approach for this situation.

It usually takes a couple of years for bats to move into a new bathouse but it only takes a week or so for martins or tree swallows to move into a matin house and both will eat about 2x thier weight in skeeters daily.

Lucy