hard to tell at that size but I would say BOP style bridsnest or stylo. Is that a white growth tip on top? said:I hope so but I'm blind and don't see it [smilie=nerd.gif]
My guess would be montipora digitata. I think I see a little color too it said:The mother colony was under the exact LEDs as mine, actually he built them for me. I've only had this since Sunday but it seems to be doing well (knock on wood)