My yellow fish I think is sick

[bubbleyumm]

So he isn't acting weird or anything but for some reason his yellow color is fading and some white cloudy areas appeared the top of his head also appears blackish. It is not ick. He is eating healthy swimming around none of the other fish are harassing him. It is a 55 gallon tank and there are about 12 other fish and all are around the same size. I do weekly 35-50% changes and levels are all perfect. Please help identify what the problem is.

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