mine liked the sand, it will move on its own if its unhappy, and fyi that bad boy will eat all your fish! if its a condy, sold often as hatian purple tip nem, its a fish eating motha!
the one i had decided to go for a stroll at night and destroyed all corals in its way! thats why they are so cheap, looks like a fantastic deal, nem for 20$ beautiful purple! yay, then it reaps havoc on all!