Sick Discus Help!!!!!!

[OfficeBasics]

I have had my discus fish for well over 5 months now and recently i have taken notice of these white/red fleshy marks on his side, all the water parameters are fine and it isn't happening to the other fish. I think it might be from My ghost knife fish who i see sometimes running his face along the discus fish, but never any biting. if you know what it could be please help. I've put him in a different tank for now

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