I have a pink pulsating xenia. It has been in my tank for three months and has been doing very well. Yesterday I noticed on the bottom of the one branch...a white discoloration with a small receding hole. There was a "hitch-hiker" crab molting in the top of the xenia. I quickly removed him from the tank. I don't know if he was picking at it or not. The xenia on that branch is not opening up and the hole seems a little larger today. Will it heal on its own? I add trace elements once a week and iodine.