fading white cloud

[gonsouth]

AI have several white clouds in a 20g planted tank along with several red rasboras and 3rosy tetras. They have been together for 2 to 3 years and all were healthy. one of the white cloud's head turned very black and his brown body color faded. After about a month, I put him in a 7gtank because I thought he might have neon tetra disease. he's been in this tank for several weeks--not geting better,but not worse either. His fins are still bright red. None of the other fish seem affected. Anybody have any ideas?

[Jannika]

Aside from the coloring, are there any symptoms such as appetite loss, lethargy, clamped fins, erratic swimming, etc? If the minnow is acting normally in every way, it may be just a genetic mutation.

[gonsouth]

He is normal in every way except coloring. He does seem unhappy away from his buddies, if it is just genetic I wil put him back in he 20g, He used to have normal coloring for about 2 years.