Originally Posted by MX#28
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.
OK let me clarify yes they can move about sort of... first they cannot move in a manner such as a true anemone. Second by extending their tubes and retracting into them they are able to "pop" up in different locations. Not something that is often done. And lastly if in fact they dislodge from their tubes that is not an indication of wanting to move it is a bad sign. Much like a feather duster leaving its tube. Typically its due to stress and often leads to death. My source is, AQUARIUM INVERTEBRATES by ROBERT TOONEN, Ph.D... he has written a rather in depth article debunking common myths about this animal.