Is aptasia the thing in the foreground? Does it dwell in little holes in the rock, have about 9 fingers, and come out now and then, just flowing in the current? I have something like that. It's got one main stem that rarely comes out, with about 5 fingers. it's a pinkish/brownish/redish color, with some creme color lines on it. It doesn't seem to bother anything. The only time I saw the main stem was when I had another rock on top and it had to stretch out farther to get into more flow.