Sorry HotChic, but that is not quite right. I had one live for more than a year in a community tank at my home. Never had a problem. BUT I believe what you said about the goldfish. Bettas are programmed to defend territory against their own kind. What I betta perceives their own kind to be is a fish with relatively large flowing fins in proportion to body size. So goldfish, fancy guppies, and sometimes angels can have a problem with bettas, but tetras, barbs, etc are fine.