[Peter Finke]

I generally use very small 12-liter-tanks and no aeration and no filters. So, there is still-water in my tanks. My fish are mostly healthy and spawn, but I know – of course – that they come from small rivers with floating waters. Only exceptionally, in nature one finds some in still water bodies. But I hate the noise of bubble filters and try to make things as easy as possible. All rotary pumps that I know of are too big for my small tanks. Therefore I have a problem.
I think it certainly would be better to have the water slowly moving, but I do not know how to achieve that. If there would exist very small rotary pumps, at best even battery-driven in order to avoid the necessity of electric cables, that would be my choice. Is there somebody who knows something like that?
As long as I do not know a solution that fits my conditions, my fish have to be satisfied with that still-water tanks. It seems to work rather well. But I feel a bit unwell by it, I admit …