demasonisrule
Fishaholic
If its heated you could try some small tetras or livebearers. Or you could get a bunch of shrimp. Or both I guess.
Interesting idea about the bonsai. I am more used to tropical plants being used for a paludarium. I'm a little concerned that the types of plants typically used for bonsai will not take well to the hot, humid environment of the paludarium. Take this into consideration when selecting the bonsai.