OK, thanks! What about the lobster?
Not sure on that one; I've never had one before. I personally wouldn't bother with one because they're supposed to be pretty secretive not to mention that it might take out some of your other inhabitants.
Your best bet is to order the cleaner crew from LiveAquaria.com; you can make your own cleaner crew and get free shipping (only on the "Make Your Own Cleaner Crew" though) provided that you meet the $60 minimum order.