BettaBabe
Aquarium Advice Apprentice
Something that might be worth trying is to let him hang out in the tank only when you can observe him. This way you can break up fights and decide if he will be compatible with every one and if all goes well. But something to remember is that when bettas go into a community some fin nipping is to be expected. It's how they establish dominance. If you don't want any at all then you should defiantly get him his own tank.