Beautiful! I bet he has some red in him. I brought my white guy home and he had blue in him in the store. Then when he got settled in, he turned all white with a red wash, no blue anywhere to be found. It seems to me like red is the first color to get drained when they get stressed at the stores. And remember vaygirl's struggle with Whiskey's red and it turned out to be marbling?? I bet that's what it is! Otherwise I think you'd see the red on other parts of his fins if it were rot or irritation.