"RichToyBox" wrote:

If you keep the number of fish down, you probably won't need any filter.
The sides of the pond, the plant roots, and pot sides will develop into
filter area. I would run an air stone, just to keep the bottom water mixed
with the top water, and keep it from going stagnant. Keep measuring ammonia
and nitrItes, and after the pond has a chance to cycle, if you are getting
either, then it would be appropriate to get some other filter on the system.

I'd treat the small indoor pond, like a big aquarium, and get an
external canister filter. Something like the Magnum line comes to mind,
it can also be used as a diatom filter, to truely polish the water.

As you point out, with a low load, you don't much filter, so you don't
need a real big one.

Inside, a good size pleco will control algae.