I am having the most difficult time treating my betta. Three months ago he was in a small 2 gallon tank that wasn't filtered, and when I noticed his fin rotting I decided to upgrade his tank. I got him a 6 gallon filtered tank and he loves it. Only thing is I cannot figure out why he will not heal. I use api stress coat as his conditioner and I do a 50% water change every week. I feed him a combination of blood worms and pellets during the week and leave one day for him to fast. His tank is fully cycled and seems to be in good condition according to his water test. His tank stays at a constant 79.5 degrees. For the past three water changes I have added the recommended amount of salt. The salt treatment seems to have kept everything under control because there is no more damage, but at the same time it isn't healing the fin at all. I just need to know what to do next to this mystery!! Any input is greatly appreciated!