Hello there, I have a crowntail betta with severe fin rot. He currently lives in a five gallon, heated tank. It did have a filter up until a few weeks ago, but the filter broke and I haven't been able to get a new one yet, though I do intend on investing in a new one soon. He has no tank mates as of right now, but previously he was in a divided ten gallon with my halfmoon betta. Unfortunately, he managed to jump the divider and the two fought - I separated them as soon as possible, but there was significant damage done to the halfmoon. However, he seemed to heal wonderfully, where as my crowntail seemed to develop his fin rot afterwards. Therefore, I'm guessing that's where the infection has come from. I've been doing water changes twice a week, adding aquarium salt, and treating him with Jungle Fungus Clear tabs as directed. However, his fin rot hasn't cleared up yet, and it's been months now. Please, I'd love suggestions on what else I can try to help clear this up.