Mantis Shrimp Behaviour

[Moogled]

Thanks rudy for the Ciliata!

I now have a mantis shrimp in my 20 gallon. First off, some questions:

1. It always approaches the side of the tank. When he gets there, he kind of bumps stupidly against the glass and then walks away. Is this normal?

2. What is a bad sign that a mantis shrimp will not make it? This guy is kind of out and about, but I'm very paranoid ever since I lost my first mantis shrimp.

3. The P. Ciliata is a spearer, so a sandbed is a must. Right now it's a barebottom tank but I will be buying sand tomorrow. Will he be okay for now?

Thanks in advance,

Marco

UPDATE: PICTURES!!