My gourami does chase him around a bit in a threatening manner but this happens very rarely but the ram is too fast for him to do anything. I've only seen this happen once but I'm sure it's happened at least a couple times. Could stress cause a fish to fade maybe?
Sometimes fish lose their color when there under alot of stress. My betta used to change his color for a day when i cleaned out his tank. Or your fish might be sick, is their anything else that is unusual.
Stress will cause a color change! You can always tell a fish's mood by observing their color! Darker colors mean confidence/aggressiveness & happiness, while lighter colors mean stress, insecurity, and fear/fright.
