fetid whiskey barrel ponds
I have started a couple of half-whiskey barrel "ponds" on my patio, and am experiencing a problem. Here is the setup:
The barrel-halves are unlined, and have the charred wood layer on the inside which is used in the whiskey aging process. They were pretty fresh when I got them, and hold water without a problem. Both barrels are in a place where they get about 6 hours of direct sun and then are shaded by the house in the afternoon.
In one, I have a small clay pot with a pond lily (Nelumbo lutea). In the other, I have about 15 mosquitofish (Gambusia affinis) and some coontail (Ceratophyllum demersum) and southern naiad (Najas guadalupensis) to help oxygenate the water (free-floating). I don't have any kind of aeration device in either one.
In both barrels, after about 2 days, the water takes on a fetid odor, becomes cloudy, and is obviously very low in DO. the Gambusia start gulping air at the top of the water.
I have tried changing the water, but after two days, I'm back where I started.
Any ideas what is going on? I would like to put goldfish in both of them, and keep the gambusia (to control mosquitos).