The appaloosa gene is very similar to the piebald gene one might be familiar with. It is a white-only gene, meaning it should be either from or near the white colour range. You do not have to colour-pick directly from the range, but if there is too strong of a coloured tint we may request you tone it down. That being said, that coloured tint should only be cream, not pink or blue.
Appaloosa should not heavily resemble Underbelly or any of the other Appaloosa variants, which are detailed below. There should be few small spots - focus on the larger holes. Think of appaloosa as not erasing the markings but instead a white overlay across the body with large holes dug out of it, showing the markings beneath.
When in its heterozygous form (Ap ap), it should cover no less than about a third of the body and no more than about half of the body. When in its dominant form (Ap Ap) it can cover a significant portion more, up to about three quarters of the body. The range below shows examples of how much white should show, not the restricted ranges you might expect from other genes.