If it is more "flat" than it is "coned" it very well could be a sundial snail. Especially if you found it within a colony of polyps. The pic is not great. It also looks as if it could be a red-banded trochus snail. They are definitely more coned, and have a black foot.
If you find that it is a sun dial snail, they can be perfect for getting rid of play's and/or zoanthids that are invasive and undesirable.