It is a male Lysiosquillina maculata. The ideal setup for them is a sandbed at least a foot deep. It will eventually dig a burrow and behave fairly normally. YOu don't have to fill the entire tank with sand. I either cut a plate of glass and wall off one end of a large system or bulid a satellite tank that I can gang to another one. I have several L.m. in back in Berkeley in glass tanks that are 24 x 6 x 18. I use a small pump to feed the tank and a siphon return. THe water has to be only four or five inches deep above the sand.
We feed our animals Selco treated freeze dried krill, frozen shrimp and the occasional damsel. The have an obligator molt every three months or so and will close up for a couple of weeks. Also, this species is fairly prone to losing their rapts, but they will regenerate. I have had several for up to 5 or 6 years, so the do pretty well in captivity.
By the way, I could a male that was 14 inches long last month on LIzard Island. That was the largest one I had seen in Australia, although there are preseved animals that get almost to 16".
Roy