About two days ago I noticed one of my black moors has his tail shredded. I separated him and started treating him with Melafix. I noticed he has been trying to scratch himself against the glass and some of the ornaments but he has no white dots. So this morning I cleaned the tank and started treating him with table salt and turned on the heater but my fish started swimming very fast as if it could not take the salt and the heat. So then I noticed it was at the bottom of the tank laying on one side and not moving. Out of desperation I scooped him out and put him in another tank with fresh water all he was doing was doing was kinda floating belly up. I decided to add some Melafix, it no longer looks like if it going to die but I still need help on treating his shredded tail, what should I do? Please give me suggestions.