SubRosa
BS Bulldozer
Rubbish mossies won't lay eggs in flowing water, I have had mossie larvea in small tanks with a circulating system, plenty of movement (granted they preffer still, butthey are not confined to it), as for fish, I have a few ponds (the smallest being 15L that has U.Aurea, Gibba, Uliginosa (on the bottom) and stellaris, this small pond has a fighter fish in it and is going very well (many months on), my other ponds (in excess of 200L) have guppies, gold fish, Gudgeons and rainbow fish (Au species) and are all very happy, sedges are a good companion, as are sarracenia, but these are to large for you, a local plant called Nardoo works very well at countering algae, as do a few snail species that don't (often) feed on utrics.
I must also add that I use a spag layer on the bottom of anything smaller than 25L, then peat on larger, adding a few old sarra leaves (cut up) will also increase tannins, CO2 and growth, but I would not advise this if algae is an issue.
On a side note my Aurea and stellaris readilly catch small mossie Larvae, but that is primarilly the guppies job.
I know that the buckets I aerate to culture daphnia don't get wrigglers, and the ones I leave stagnant to attract mosquitos do.