Hi guys, I have a tank with a betta sorority of 5 and unfortunately one of my girls has fallen ill and I would really appreciate if anyone could provide me with any information on how to help her. I've done lots of research but I’m just not sure. She’s has a swelling on her left side and her body seems to be curved. She’s struggling to swim upright and I had noticed a tiny swelling last night but over night it has grown bigger. I do regular water changes and I always test my water. I’ve had them for over a year now and this is the first sick fish I’ve had. I’ve removed her from the big tank and placed her in a separate container to quarantine her because all of the other fish and perfectly healthy. Her appetite is fine but she has become slightly inactive that what she usually is. Thank you so much for your help.