u have to place them, he won't move. i wedged mine into the live rock. didn't crush him but held him in place and he more or less glued himself in. and just fyi they do from time to time loose their heads so if u see it floating around in the tank don't worry, he is growing a new one. i failed to realise this and went to remove him and just pulled on the tube which ripped off and there he was growing a new head. found out from my lfs that this is normal as they grow. so just to let u know lol