Our female mandarin started eating frozen when we first introduced Rod's food into the tank. A LFS employee said the same thing happened with his. She will occasionally eat frozen mysis and brine (we never feed just one thing is always a few mixed in together), but does not seem to eat it every time, just when the mood strikes her. Our scooter blenny eats the frozen too, by the way. But the male mandarin has never been witnessed to eat anything that's not hiding in a crevice of LR.

If you're really trying to get your mandarin to eat frozen, you could give Rod's a try. I bet we're not the only MAASTards that have some in their freezer that they rarely ever feed anymore... (since that red slime algae discovery).