I am looking into getting a Mandarin that will already be feeding on frozen
frozen food for any dragonet is nothing more than a supplement. it should not be your intended primary food source for the fish.
the primary food should be their ability to graze for their pods.
reading through your past posts it looks like you're bringing up a 120 with an external macro tank for algae/pod cultures?
have you considered adding a shared sump between the two tanks? if space/configuration permits it, plumbing the two together could benefit you with increased water volume, and what would essentially be a display refugium, allowing water and tiny critters to flow back and forth between the tanks without rock swapping. i'm actually planning a similar setup when i get my 150 running later this year.
if you're looking in to additional supplemental feeding for you mandy, check out the PaulB style feeders:
http://reefcentral.com/forums/showthread.php?t=2113800&highlight=feeding+station
these work well for newly hatched baby brine shrimp.
white worms can also be cultured and fed. i will sometimes also feed black worms to mine, but since they don't last more than a few seconds in saltwater, this is more or less an occasional treat.
culturing pods is a pretty easy/fun thing to do too. requires minimal attention, and never hurts to have them on hand.
although if you have a decent amount of rock and sand in your 120, that should be sufficient for one normal sized dragonet. even more so if you do a sump/fuge, or a display fuge.
