Mine sure do reproduce like aiptasia!! I started with one, and now I have about two dozen. I killed a bunch of them with kalk paste, but some of them are wedged so far into rock crevasses that I can't reach them to smother them. And there are about 4 corals on the rock that they're on, so I can't take it out of the water or do anything to the whole rock.
Well, my xenia don't have a sting either, but I still have to prune them. The majano are taking over areas where I have different zoanthids, so it's not a matter of them stinging, it's a matter of them smothering... They just spread too quickly.