Moving live rock with fish/inverts/corals in the tank

[eli@fijireefrock.com]

if your system is fine and been setup for quite some time you shouldn't have a problem and its best to have all pumps off for the time of move.
If your system is large enough and could handle the bioload I wouldn't worry about a single dead snail or a crab. if you worry about and individual invertebrate, then you will be spending more times moving things around then enjoying your tank.
Just like Titus99 said don't stir up the sand as that is where the h2s will be released from.