Wrasses that sleep in the sand do not dive into the sand like we dive into water. They cannot hit the rock in injure themselves. What they actually do is vibrate their body really fast. This part the sand and they slip into it. They swim around and choose the right place and gently "vibrate" into the correct place. It is really neat to see sand sleeper wrasses vibrate into place. it looks like magic. Like Jesus parting the Red Sea.I have several RFAs and I doubt a wrasse would let that happen. They are just asleep not comatose under there. I’ve tried to catch a sleeping wrasse and failed as they are still aware and fast.