Originally Posted by PerfectDark
THey cannot move, the have similarities to anemones in regards to eating and stinging. Although their poison is the least toxic of all anemones. It requires a sand bed becuase it burrows. And just make sure there is room between it and your corals.
They CAN move. They have a few methods of locomotion. 1st, they burrow in the sand and can move from place to place through a tunnel network under the substrate. 2nd, they are very bouyant and can dislodge from their tubes, if they are unhappy, and go floating around the tank untill they find a new home (this is a good time to have sponges on the intakes of powerheads). If they are in a good location and are fed enough, they don't seem to wander much, but they are certainly capable of it.