I'm working on a small semi-self sustained aquarium. I already somewhat succeeded with another tank, but that had a herbivore who wasn't a fish. Now I've got a larger tank I'm hoping to stock with some fish in a few months when it matures, since the last live-plant eating herbivore in my last tank won't be a herbivore by then. :p I also considered plant-eating snails but I'm definitely looking to have between one and four smaller fish instead.
I do know my LFS carries rainbowfish so that's a good candidate. I was also thinking I could possibly add a single molly since a lot of the basis of the tank is hair algae, more than enough to sustain an adult molly, but I understand them to be messy fish.