Originally Posted by Marieukxx
I'm really worried about it as I've read both good and bad stories. Is it true that bettas that look different are less likely to fight?
No, it's not true. Sometimes different contrasting colors may not fight at first (depending how they were raised) but eventually they will have an "alpha" contest.
If the new females were in a sorority, they would probably be more docile. But your current female has been alone for some time. She will probably be aggressive, at least when you first put them together. This usually triggers others to flare.
You have to let them fight a bit. Usually most females from sororities won't go to the bitter end and will swim away after a few bites. But those who were in solitary might hold her territory.
Keep an eye on them for the first 30 minutes. If they don't fight, they should get along. Take out any female that's too aggressive (always chasing and biting others).... flaring is ok, but fighting/biting is not.
Hope this helps