No. I had touched my friend's blue linckia several times when I acclimated it. It had gotten stuck in the bag it was shipped in, so I had to remove it by hand. Before you touch anything in your tank, or even put your hand in your tank, you should wash thoroughly with a mild antibacterial soap and rinse very thoroughly. It is ideal to not have to touch anything at all, but sometimes it is necessary. As for damaging themselves on rock, there is no real chance of them simply hurting themselves by moving across a rock. If this were true, they would all be extinct for lack of mobility in the wild. Now, if a rock should FALL on them, that would be another matter. lol