i have 3 female bettas well 2 . I bought my bettas from petland. I had a white one and green and newest addition a purple one. (after the white one had passed away ) I had no problem with my green one it’s still very happy and healthy. 2 days ago i had went to go change the tanks of the bettas. I had cleaned the green bettas tank with no problem. However when I was cleaning the white fish’s tank, as soon as i had placed it back into its original tank it was going crazy. (The fishes had same everything including the same temp. water. )As soon as i placed it back it was knocking it’s self against the tank. It was hitting herself with so much force even i felt it. I was very scared and suddenly it was swimming on its side so i thought it broke its fin hittin herself. after about 30 seconds of swimming sideways she had stopped and just flown to the top. I started to see if it was ok but it was floating upside down when i found out it was dead. I researched for an answer but never found 1