I have a platy that’s got a white spot on her lip, it's been like this for 4-5 weeks, and her mouth is not entirely straight due to this, the spot doesn’t seem to get any better or worse, still eating and moving okay, I have treated the tank with Myaxicin, Melafix but still the spot is still there. I have now moved the fish to my hospital tank and treated it with aquarium salt & melafix. I am sorry but don't have any pictures. Does anyone know what it could be? Can fish get ulcers as this is what it resembles?