I've honestly never seen it grow on anything but rock, even on a bare bottom tank. I mean it's gotta make some sort of skeleton for the fleshy polyps to live on, but I've never seen it when not on the rock work, but do note I'm not saying that it can't, I've just never seen it happen. But I do know when you see other similar type of LPS like favia growing on frag frag discs they're not making a very big skeleton at all, in fact sometimes it looks like they're not making any skeleton and they're just laying out a paper thin layer of coral. My first thought is sand my irritate the leading edge of the coral, so it won't grow in that direction though, and again with the skeletal nature.
