if you ever forget that bettas have big personalities, throw a few ghost shrimp in with your boys.
they sell em for 33 cents at petsmart, so i got four to put two in with each gus and finnick and OH MY GOSH it was so funny. finnick is considerably less passive, so he was just really interested in them; sorta followed them around a bit but didn't bite or flare up or anything. gus, on the other hand. he was nipping and chasing and flaring like a madman and they were jumping out of the tank and it was crazy. i ended up taking the two in gus' tank away and putting them in my other tropical tank because i was afraid it was stressing him out too much
ugh i just love bettas