I have four female bettas, one of which is a fancy Thai, and I'd like to put them in my community tank, but every time I try, they fight viciously and I have to quarantine them again after less than an hour. What can I do to improve this situation? It it impossible for them to co-exist? We tried letting them duke it out a bit, since I read that they have to establish a pecking order, but it got really nasty, and we had to seperate them before someone got seriously injured or killed. Any advice??