I've gotten some great suggestions on here for additions to my 20 long, which currently has: 5 Colombian Tetras, a guppy, and a platy. Both male. Things that have popped out from the suggestions were GBRs, Bolivian Rams, and apistos, especially apisto cacatuoides and apisto borelli. Would I be able to have a single specimen thrive until I had room for the other? If so, which fish would work solo? I'm still undecided, so I'm still open to any suggestions that you guys have! (Except for adding more livebearers, and I plan to increase the Colombians from 5 to 7 if I find them at the LFS). Thanks again!