I keep Koi, Goldfish,dalmation lyretail mollies, and neon Longfin rosy barbs. I have also kept Electric blue Ahli, Demonsi, and Daffodil Brichard African cichlids during the summer in the past( BTW, WITH GOLDFISH, and they breed and didn't harm the goldfish!). Other fish I have kept that I really enjoyed are white clouds, Dwarf sunfish, Golden cochahoes, Paradise Gourami, and Odessa barbs.
Trying to think of another small species to try next year in tub gardens. I'm really having fun with these small aquatic gardens but keeping one or two fish in each on for mosquito contol has become somewhat challenging. I need something small that isn't a prolific breeder, that can handle a large swing in temp. ranges, and can't be over brightly colored as the brighter the fish the more they attract prey. Trying to locate the smallest livebearer the Least Killifish (Heterandria formosa) to give a try. I had them once many years ago and I'd love to try some of these little natives again. They are actually suppose to be common and local to my area but so far I haven't located any but the hunt is on.