My Coral Doesn't Like Me, Please Help!

[sir crabsworthy]

i've just put live rock and a single cocoa toadstool leather into my 30 gallon tank and it doesn't seem happy. The coral extends its tenticle things for around 30 mins then retracts them, it did this around 3 times a day. Yesterday it seemed even more unhappy and hasn't really put its tenticle things out since then. how do i make this leather happy? is it normal for it to do that? what temperature will it function best at? does it like high end salt levels or less salt? we also found a stow away crab, around 1cm big, that likes to eat bits off the live rock. will my crab hurt the live rock or leather?
any help would be good because i can't find much usefull information on coral.
thanks heaps

 

[ibbledibble]

You might be better off posting this in the saltwater section.