I have a well established 10 gallon planted tank. I keep 3 females ans 1 male peacefully. The male is about 1 year old and the females are wthin 6 months of him. I recently got a second male and about a week after getting him my tank setup quit working. I had to put him in a large jar and set that in my community tank with the other 4 bettas. My first male never flared and seemed not to care about the new male. After 5 days I decided to cautiously introduce the second male to the tank. I was ready to separate them at the first sign of aggression. The new male swam around with the females rubbing against him for about 10 minutes. My first male watched him but again didn't seem to care. Then the new male saw him and slowly swam over to the plant he was relaxing in. The two brushed bodies twice with no flaring and then the new male swam away. Now it's been almost 4 days with no sign of aggression yet. Neither male has nipped fins or missing scales. They even pass each other on their way to the surface. My fish are all trained to feed in different corners to minimize aggression, so maybe this helped my male accept another male in his territory. I provided dozens of hiding places, including a cave under the gravel that's too smallfor the males so the females can hide if need to. I understand the history of bettas and have read several books. I've spent years raising them and am experienced with their handling and care. I have not heard of anyone else achieving this level of betta community tank and was hoping there has been some exploration into it.