u/Kitchen-University11

I need help identifying a growth that has popped up on my black moor goldfish. It has appeared in the last week but may have been developing longer then that. It appears to be a solid white growth on her right gill and not spots. My water parameters were all within range although nitrates were just a tad above normal. I have isolated her to a hospital tank and treated with some blue but unsure what i need to be treating her for. Thank you to anyone who can help