Scolymia and cynaria appear similar. My understanding is that cynaria are more translucent, and tend to swell a little more. I have what I've decided is a scolymia, and it looks just like the green one above (except it's red). It's obviously possible I ID'd my own critter wrongly, though.
In any case, care for both is about the same. I placed mine on the substrate, and feed a couple times a week.