The Mandarin was my first fish to add to my newly cycled tank. He eats a frozen blend from my lfs, he will only eat the nano blend (which is just heavily blended into a puree) he has been doing better then my other tank mates and is growing fast. I just recently added a 12oz bottle of copepods and the only fish who seems to really be enjoying them is my bangaii cardinal. So I believe they are not as hard as people think. Either that or I got a non picky Mandarin. Also he seems to eat a lot off the live rock (which might mean the lr I bought from the lfs was already seeded with them)
I'm just simply saying he had been eating like a champ for about two months now, very active most of the day eating. When he isn't out eating, he is just chilling in the pineapple under the sea
for the record, I didn't claim anything(as I don't have many of these fish, just one, so this is not to be taken as me claiming factual evidence), just sharing my experience so far with mine.