I have 2 Ryukin gold fish, I have noticed that one of them was losing color a month after i bought them. The fish used to be of a nice bright red color with numerous black spots, now parts of it are white, the rest is pink and no and almost no black spots. The fish is young, and was not fighting, they live in peace with each other. Other than that, both fish look good, fins are beautiful, they are active and happy, Whats with the color change? please help