I got some xenia about six months ago. Cool but a pain in the rear. It has spread and devided more than anything I have seen. A small piece (one head) is now about twenty times larger. It also likes to move around. I has moved to the highest light and highest current. It is right at the top of my tank in direct current. I put it at the bottom. It also has been moving onto my montipora. Just this weekend I had cut it off of the mont, and drop it on one side that is void of any good activity. Hopefully it will stay there.