| What kind of lighting does the tank have? I know sometimes, if the lighting is not full spectrum, a goldfish will fade, then get it's color back when it has proper lighting again. Other than that, it almost looks like either a reaction to ammonia (but you tested, so it can't be that) or a burn. Could she have jumped against the light and burned herself? Goldfish can be very curious, so if there was any way for her to jump up and bump the light, it may be a burn. Ammonia, injury, or lack of full spectrum lighting are the only things that I can think of that would cause her to lose color - especially since she is acting normal and eating fine. |