Hello! Over the course of a day I noticed my Ryukins red patches fade away and now they are a dull redish white. He's eating fine and swimming around normally so he doesn't appear to be sick. He's in a 55 gallon tank along with a black moor and a lionhead goldfish, whose colors havent faded at all. I've had him for about 3+ years and am not sure why he is suddenly changing colors. There's a heatwave where I live now and the tank temperature has been at a constant 80+F. Could the heat possibly have anything to do with it? Any answers would be appreciated! 
