Female Betta picking on new Female Betta

Are there other females? You can't have just two together, one will end up destroyed. The idea with sororities is that there are enough females to spread out the aggression so not just one fish is being picked to death on.

NO she is the only one :/ maybe ill put them two in the larger tank and then my male Lihgtning in the smaller one

The tank size isn't going to make a difference, you really should separate them. Unfortunately, it's not like they will ignore each other the more they have room to swim, they hang out in the same areas and so then will still be picked on the same. Even if you have to float one in a breeder net or box, it would be safer that way until you either get a different tank or get more females. The start of a sorority should have no less than five females in it.

Well she will be a little safer for now, I bought tank dividers so just waiting on those in the mean time the bigger tank has better hiding spots so i will just keep an eye on them, The bigger is a 55 gal

update: I got the tank dividers in!!! just hope i did it right.

I'm glad you bought tank dividers.

as a rule of thumb, if you are going to have females together then it needs to be in a sorority setting - meaning 5 or more bettas.

there are VERY FEW cases where two females have lived together peacefully -- but this is usually because they are sisters and were never separated.

all bettas are territorial. The original female will be extra territorial since she has been by her self in her own "territory". Youve essentially jarred her, which makes all bettas more aggressive. Now that youve added an intruder she will attack.

Best thing to do is separate the new one, you may be able to desensitize her to the new one by keeping her in sight but out of reach, but yeah, if you put them together its probs best to put them in the bigger tank