This is not real evidence, but this should be a healthy fancy goldfish, compared to a stunted one: http://4.bp.blogspot.com/_HHlesUNOY...AAAiw/0Gr6vumOEkw/s1600/post-9-1145600416.jpg As you see the stunted one has much larger eyes, and should also have larger eyes. As said i found this under and article about stunted goldfish, but i do not know if this might just be to different goldfish (There so meny of these goldfish species, and some of them have large eyes, so maybe it has some large eye goldfish genes or something) Or maybe the healthy one is the one with the big eyes, i've just heard meny Places, that stunted fish get larger eyes and organs compared to body size, and this eventually kills them, so when i saw this Picture under and article about stunted goldfish, i just assumed the one with the large eyes is the stunted one.