We have 1 female betta fish who we bought 4 months ago that lives in a 10 gallon tank with 2 other female betta fish. This betta fish looks to be somewhat bloated but also there is a white patch on her body. It is possible that she might have dropsy? However her scales aren't pineconing. It looks like she got into a fight with my other betta, Pip, as her fins are torn. This hasn't been her first fight so could this have been a result of a previous one, and it looks very serious. Lately she has not been eating very much and has chosen to hide among the many decorations in the tank rather than interacting with the other fish like she used to do before. I know that this can sometimes be the result of a fight but it seems like much more. I've also been away for a week with someone only feeding the fish. Could this possibly be a fungus from a dirty tank? I have since then decided to fully clean the tank out. She's not having a lot of trouble swimming so far.What could I do to help her and what is it?
There is a heater for the tank, but we don't turn it on because the room and water get warm enough with the temperature staying between 25 - 28 degrees Celcius. We also currently have a filter who's cartridge is replaced every month and the water in the tank is replaced twice a month along with a complete aquarium clean, including using a gravel vacuum, adding conditioner, bacteria supplement, and an extremely small dosage of melafix. I'm thinking about putting him in his own container for a while until things get better, or I can figure out what I can do to help.