Our two black moor fish are looking progressively less black - they're starting to look grey with hints of gold here and there. Otherwise they seem well. Is there anything we can do to restore them to their former colour? (They're fed on the usual fish food sticks plus the odd pinch of freeze-dried bloodworm.)
Black Moor fish are omnivorous - to give them a good balanced diet why not try some brine shrimp or daphnia in addition to bloodworm? Apart form this, are they kept in a dark room?
With goldfish it's dark rooms that cause them to lose their colouring - try moving the tank to a sunny area (obvious not in the direct sunlight for too long as there is a rish of over-heating the tank) and see if their colours improve!