Actually, bettas can live quite peacefully with community fish, like tetras, cory cats, and the more plain colored guppies. As long as you dont put anything that looks like a betta in with him, he'll be fine. If you're really worried, then just put a school of cory catfish with him. They're peaceful bottom feeders that get along with most fish. Add in that bettas mainly stay at the top, though they will explore sometimes, and there's no real fighting. While my betta was a little worried over his guppy friends, he pays no notice to the cory. (I'm getting the rest of the school tomorrow; dont ever keep them alone!) Bettas are not vicious killers of all fish like some would have you believe. I was worried about adding fish to my betta's home, but they get along great and it makes the tank all the more beautiful.