I have a peppered Corydora that is in pretty bad shape--I can only assume that my Betta did it--he has part of his tail missing--his dorsal fin is damaged and he has an open wound near his anus. I doubt he will make it, he is able to swim but he isnt doing very good. He mainly lays on the bottom and breaths heavily. His colors are good--actually he is darker than the others in the same tank at the moment---they are eating and their colors seem to fade while they eat--weird.
Anyway, I did a 50% water change--was time for that anyway--thats when I noticed his wounds. I took the Betta out and put him in my other 10 gallon by himself. I added a dose of Jungle bacteria and fungus remedy, took off my DIY filter difuser ( water bottle split in half and attached to the filter outlet to slow the flow down ) so the water would have plenty of aeration and gave the injured fish a salt dip.
The tank is a planted tank with great water conditions---I tested with my API kit before the water change.
Any other suggestions?