So, it has been awhile since your post....so if your wrasse is still alive you should probably have seen it by now. I did want to let you know though that they do burrow in the sand at night or when they feel threatened. I have never owned one that didnt do this. As I recall, I dont ever remeber not seeing them for longer than a weeks period, usually saw them daily....in fact, with one I had, I he would pop out of the sand precisely 10 minutes after the lights came on in a.m. Cool fish, easy to keep. I havent had one in years but they were always fun to watch. Hope yours is still alive.