My betta lives peacefully with 4 platys, 2 oto cats, and a snail in a 29 gal. I have one "problem fish" in there now which is a bleeding heart tetra that nips at my betta's tail, but I believe this behavior is caused by his lack of peers (i.e. Tetras are schooling fish, without their school they become timid, nervous, or stressed and may feel the need to assert dominance in the form of fin nipping). Planning on getting him some more friends to regain order in the tank.
According to the Aqua Pilot App, bettas are compatible with:- African Dwarf Frogs
- Bala Sharks
- Balloon Belly Mollies
- Black Line Rasboras
- Black Phantom Tetras
- Black Tetras
- Bleeding Heart Tetras
- Bloodfin Tetras
- Blue Ram *
- Boesemani Rainbows
- Borneo Suckers
- Bushy Nose Plecos
- Cardinal Tetras
- Clown Loaches *
- Cory Catfish
- Dwarf Loaches
- Eclipse Catfish
- Emperor Tetras
- Ghost Catfish
- Ghost Shrimp
- Giant Danios
- Glowlight Tetras
- Guppies
- Hammers Cobalt Blue Lobster *
- Harlequin Rasboras
- Hatchetfish
- High Fin Platys
- Lyretail Mollies
- Mollies
- Mystery Snails
- Neon Tetras
- Network Catfish *
- Ocellifer Catfish *
- Pearl Danios
- Penguin Tetras
- Platys
- Sailfin Mollies
- Scissortail Rasboras
- Serpae Tetras
- Silver Dollars *
- Spotted Danios
- Striped Raphael Catfish
- Swordtails
- Zebra Danios
- Zebra Loaches
* Sometimes Compatible - Suggested for advanced aquarists only.
Always make sure your tank is big enough for the species you plan on stocking. And, like carbonxxkidd and aemaki09 said, it depends on your betta and the other fish. Sometimes compatible species might not get along due to individual personalities. As for my male, he doesn't seem to mind the platys (3 females and 1 male) since they keep to themselves, but he enjoys a short chase once in a while. When I had two bleeding hearts, they kept each other occupied and ignored the other fish in the tank. But again, since i'm down to one, he's began nipping the betta. This has only been happening when I fast the tank, though.