I'm happy to be worried about this, because it means my corals are growing! When I got this Tri-color frag (which unfortunately looks more like a mono-color right now) a year ago, there was lots of room between it and the ORA Plum Crazy next to it. Now they are about to collide, so I'm wondering if I need to frag them to keep them from stinging each other, or if they will coexist.