yes it makes its home in the sand if not enough it will spend all its time in hiding to get away from any dangers and from what i read they wont come out to eat and die of starvation because they couldnt make a home in the sand
Not real deep, as long as they have a large shell or some thing to use for a roof. I have on that lives under a large barnicle with only about a 2" sand bed. I love Jawfish, the only thing that I don't like is the nearly constant digging can make my tank cloudy. Oh and make sure that some food gets near their den as they won't venture far from it to feed.