Well yes. It depends on the temperament. Sometimes it is better to be on the safe side though. I guess I don't know the amount of knowledge that the poster has about bettas. I suggest that if you really want another fish, get the Betta first. Watch him, get to know his temperament. If after awhile he seems gentle enough, try putting another fish in. Watch them very carefully though. I'm sorry if it seemed like I was being rude or anything, I just want you to know to be very careful with that size of tank.