It's a popular misconception that keeping Siamese fighting fish in small bowls is perfectly ok for them. The truth of the matter is, just because they can breath air it doesn't mean they should be kept in a tiny container. They should be kept in aquariums not bowls, so provide her with the bigger tank. Female Siamese fighting fish can be kept together and can be kept in community aquariums with no trouble. It's just the males that wreak havoc on each other.