Fungus on a Discus

[Aquarium_Lover04]

My small red turq discus had a fin injury which I thought would heal naturally although it now has a small amount of fungus on it I have now noticed that it is also looking a bit thin.
I have decided to take it out away from the other fish and put it in a separate tank to treat and 'fatten up' before I release it back into the tank. I was just gonna try using pimafix because I have used it before and have gotten results.
Am I doing the right thing? Or should I try another anti-fungal medication?

[jlk]

How are the water parameters where he is now (amm/nitrite/nitrate)? Can you possibily post a pic?