Thing is, with the exception of the obvious fantasy elements of the site, Rescreatu generally tries to steer its features (colours, pets, etc.) in a more logical direction than most petsites. That doesn't quite get across the point I'm trying to make, actually. Look at our currently available colours -- hatchable colours all mimic schemes that you would see occurring on a real animal. Dye kits are only lurid and garish because the as sumed story is that you're "dying" your pet an unnatural shade by hand. Again, perfectly believable. That's why we can't "paint" Creatu different themes, like Neopets' Strawberry and Jelly examples.
I'm not entirely sure what you're suggesting -- be it just making a Creatu the opposite colour scheme of what it is right now, or doing a full invert on the image itself -- but either way, without a convincing, could-be-real-but-isn't explanation for the colour, I don't see it fitting with the site's style.
...As hilarious as it would be to have hordes of blue-eyed, white-outlined, black albinos running amok. xD