They are telling you to wait on the mandarin because about the only way you can successfully keep one is to have an active "pod" polulation in the tank to provide it food.
I am assuming you don't know this (if I am wrong, I appologize) so I am trying to include as much information about it as possible.
Mandarins don't eat flake and frozen foods very well, and brine shrimp doesn't seem to keep them going for very long (although you could use them to suppliment the pods). Your "pods" (little humpbacked shrimp-like crustaceans) will establish in your tank if you introduce them (they can be obtained by live sand, live rock and macroalgae purchases) and give them time without being preyed upon. You will see them when you have them... just look at your rock closely around holes and in your refugium (if you have one). Once you are sure you have a lot of them and they are reproducing then introduce the mandarin.
I think you will also need to add about 50lbs more of live rock. Keep us updated. Has the tank cycled?
