Aphotic Phoenix
Fish Addict
If you haven't considered shrimp yet, despite all the recommendations, I'd urge you to check out petshrimp.com to see some of the varieties available. Also, the dimensions of the tank really matter as well...for example I don't feel bad about keeping my betta in 2.5 gallon b/c it's almost as long as a standard 5 gallon, but there are some small tank configurations that don't give much "run" space.
