Right ok i do have a 28litre tank i am cycling at the minute, but as for her not getting along with the other females i bought all 4 from the same tank from the petshop and petshop said they were all sisters so guessed they would be fine in a big tank together, i sit constantly watching them and like i said never witnessed aggression towards her unless its happening at night. If she was been bullied like i said i put her in a big breeders net to seperate her and she jumped straight back into the big tank you would think she would stay in net away from the rest of the females
You have to remember that this is not how bettas live in the wild. You're putting them in an un-natural situation by expecting females to get along while staying together, with no escape from each other. So betta sororities are always a very difficult balancing act, and often end in disaster.
In the wild, new betta fry live together in the same area without fighting while they grow and mature. But once they're old enough, they begin to strike out on their own. Males go and find their own territory, and guard it fiercely. Females are natural travellers. They venture though different water ways in search of a male they find acceptable to mate with. Once they've mated and eggs have been released, the female leaves, and the male will chase her off too. These are a solitary fish. It is in their genetic make up to live this way, the way they've evolved to be successful in their environment. When people thought bettas lived in puddles because they found them in tiny muddy puddles, they assumed they lived like that all the time. But no. It's because of their environment, so when water levels are low, they can breath air using their labyrinth organ, and survive conditions that other fish could not. Those fish were usually ones that were using small water ways to travel in search of territory or mates, and it's not how they *enjoy* living- it's a way they've evolved to adapt to their environment so they can survive travelling like that and the seasons in their location. It's temporary, not how they live usually, which is in huge bodies of water.
They live together when young and immature. When people suggest sisters for a sorority, it's because they're still juveniles in the store and haven't been separated yet, so they haven't yet had that "get away, go find a mate" instinct kick in yet. They would fight with an unknown betta if it was introduced, but the ones they've been raised with are still okay. So that's why everyone says to get sisters when you want to build a sorority.
But now your fish have matured, and instincts tell them to go, find a mate. Leave this baby area and your siblings. But they can't. Mature betta don't live with other betta in the wild. The males are fiercely guarding their own territories, the females travelling alone, only staying around another betta if it's a male she's mating with. If a mature adult betta that had left the nursery area later ran into one of their siblings, they're not going to be friendly. By that point, it's just the same as any other betta. Drive them away, and fight if you have to.
I saw your previous post about your tank, and you said you're new to the hobby. May I ask why you started with a sorority? Because they really are difficult to manage even for experienced keepers who have kept bettas for years.
