Looks like you are correct on the T.geoffroyi. Unfortunately, due to my rambunctious maroon clown and this species' difficulties in removing sediments (read up on it), I can't take the chance of putting it on the sand bed. I'll see what I can do about finding a cupped rock that I can put some sand in and replace it in the same area. The thing is doing great right now and I don't want to mess with it too much. It has a nicely shaped base that sits well and the rock I have it on currently is covered in smooth coralline.Nice looking corals. I believe what you have pictured is actually Trachyphyllia geoffroyi. It generally does much better when placed on a fairly fine sand bottom...their tissue is tends to get abraded and torn when placed on rocks.