I haverecently set up a whiskey pond barrell. I'm having trouble keeping fish alive in it.They seem to be gasping at the surface and are very lethargic. This would suggest a lack of oxygen? I have several plants in there including a lily the leaves of which seem to blacken after a while. There is a also quite a pungent smell within the barrel. Due to the lack of fish there is a huge amount of midge larvae. I don't have a pump and don't intend to use one.

I've changed the water several times since setting up.

Can anyone help with the above. Suggestions for the fish and midge larvae problem?

The smell?

cheers