That is part of what I find interesting. The BP's have proven variable for color and pattern, but the body types seem identical. I don't see size, shape, or behavior differences. Compare that to the various breeds of dogs, pigeons, chickens... The BP has so far been remarkably stable for everything BUT color and pattern.

I am curious what drives the genetics in gold fish. You are correct about the morphs being so much more extreme - even, really, for other animal categories. No one has come up with a pigeon that has bulging enormous eyes that only face up. We have pouty full-breasted pigeons, but no hunchbacked pigeons with enormous trailing tails and fleshy wens growing over their foreheads. Gold fish morphs really are extraordinary.