How much sunlight does your fish get?
"Color Changes- If the goldfish was once black and has turned orange or was once orange and is turning white it could be that the fish has been kept indoors and without full sunlight. (which would be the case if you had a tank in the house). The fish is suffering from pigment loss in the skin. Red Capped Orandas are famous for losing the red cap. Orange comets are famous for turning white. The key is as follows:
Water quality is great
Discolored areas are not raised compared to the other skin
Discolored areas are not depressed under the rest of the skin
Fish is acting good, eating normally, and fins are erect and white ( no hemorrhaging) "
aka Cycling Guru and the Ich Slayer
*glares at Terry and QTOFFER*
Card carrying member of FTAS & GCAS.