Is the growth fuzzy, can't tell from the picture. You can try treating with either melafix or primafix, I can't remember which one is for what. It's not ich so thats a great thing!
__________________ 180g- Mostly BIG fish and some coral. ~80g Nuvo- My coral tank with "happy fish"~ 90g- FOWLR Not the not happy type of fish~ 125g- Freshwater Malawi Cichlids ~10g- Nuvo- The refugees from the Ich of '18