make sure you properly cycle your tank before adding fish, i recently made the mistake of not cycling and lost quite a few fish. ive got a 29 gallon with a beta, a baby tire track eel, 1 angelfish, 4 khuli loaches, 1 molly and 2 little pitbull plecos. the beta pretty much gets along with everyone, i have an ornament squidward house/easter island head that the beta pretty much claimed as his house. he sometimes does that posturing thing betas do when another fish gets close but he has never attacked. im under the impression a single beta will be fine in pretty much any community aquarium just make sure you dont have any fine nippers in with the beta or he will get shredded and of course never add another beta. i like tossing a single beta in any community tank as they are nice looking, interesting and hardy fish, the beta survived the cycling process no problem. you could also add a few more fish than i currently have in my tank if you would like but the more room for your fishies the better. lastly ive been on a freshwater eel craze lately and a long tank with a sand bottom would be great for a small eel, once it grows however a larger tank would be required. if your planning to buy your fish at a pet store you could also ask the person working what fish would work best in your tank. hope this helped a bit.
