They're all the same. Morphs depend on lighting and water conditions. You could probably get them to plump up to a decent size in the right conditions. I've seen colors ranging from green skirt, greenish yellow skirt, orange center, red center, black dot, blue dot, or even neon green dot inside blue dot (kaleidoscopes). I've seen all of these morphs on the same polyps in my tank while I cycled through different lighting schemes. Skirt lengths also vary depending on flow. High flow equals longer skirts.