Purple Tile Fish doesn't eat and hides all the time

[h9151105]

I've bought 5 days ago a wonderful purple tile fish. Since then it is hiding behind the rocks and doesn't eat also. I've tried to give frozen cyclops an shrimp but it is not interrested. It is getting critical I assume. Please help,what can I do?

[Marshall O]

Is it in a QT by itself, QT with other fish, or DT? If DT, what size tank and how many other fish do you have?

[Deinonych]

Also, do you have substrate in the tank? They need at least 3" of substrate for burrowing.