Here's a picture of how he looks... He literally looked fine one day and then the next day started losing his fins, and as I've been trying to figure out what to do the past day or so (changing his tank out, trying medicines, etc.) he looks like this now. I just started treating him with Maracyn 2 today along with epsom salt and the food you recommended me with the garlic guard, but he doesn't seem to like the food. :( He'll only eat his old food which is TetraMin Tropical Granules.
Also, right next to his fin is where the wound is which you can't really see. You have to look from kind of behind him... but it's a beige spot that has no scales left on it, and as you can see part of his fin is missing. He still uses it sometimes though and is active, but often I'll see him swimming with only his left fin. :(
As you can see though he looks really bad. I'm worried he's in constant agonizing pain by how he looks, despite how active he seems to be. Do you think it's possible to save him at this point?