Can anyone help? I have had Black moor fish for over 15 years now. Each one has lived for approx nine years and I have looked after them with great care and expense. All four of them slowly changed from black to orange/gold in a matter of months after putting them in the tank. To be honest, I thought that was just normal, but from what I am reading, it is unusual. The one I have at present is around six years old, but is changing colour for a second time, from orange/gold to silver. It just started happening yesterday but is extremely rapid. Any thoughts? Is it water temp, food, light which causes color lose?