Figured I'd give my 2 cents since I have 2 dragonets that are eating prepared foods. lol
My mandarin is an ORA one that supposedly ate pellets. HA! Not when I got her home she didnt and only ate pods. i started by feeding 3 times a day an assortment of frozen food. i started with cyclopeeze and baby brine. I tried everything i could think of, I mean I had over 12 different foods in my freezer at that time. She eventually started in the small frozen and has worked her way up to bloodworms, which she really loves and eats like spaghetti. lol
My scooter was actually easier, well, it took less than a month with the same feeding protocol and he was eating mysis and bloodworms. The mandarin took over a month and luckily I had enough pods in the tank for her to eat while she transitioned.
I've had my mandy for about 6 months or so and she'd a fat little sausage now. Same with the scooter, two little fatties. LOL I still feed twice a day though and I watch like a hawk for any signs of them turning down frozen food. It's really a gamble with these fish. An established tank is probably the best way to go, not sure if I would do it again with the mandarin but she is an awesome fish!