not all female betta's get along.
Horizontal lines running down the sides of a betta mean that it is experiencing stress. Stress can be caused by any number of reasons, including water quality and fear. If one female is constantly showing horizontal stripes, this may be an indication that the other female/s is/are picking on her.
Vertical stripes, also known as bars, can be a sign of readiness to breed or one of aggression/dominance. Females can be aggressive with males as well as females, and it is natural for a female to flare at a male.
She may even bar up out of aggression, which is why vertical bars are only one of several signs of readiness to breed with a male. If your female becomes barred when facing another female, it does not mean that she wants to breed with that female.
It is a sign to "stay away
Sometimes, a fight may not break out, at least not at first. The females may "pose" for one another as an indication of how "tough" they are. One may attempt to make the other back down.
If one fish is willing to let the other be dominant, fighting may be avoided. Even if one doesn't fight, the dominant betta may assert her dominance over the other from time to time to test her.
srry sometimes I talk to much and give to much info. just wanted to make sure you knew
(I do not have any females only one male but I like to research on females alot)