Divaman, I think you kinda answered your own question when you refer to your mandarin "destorying" your pod population...what's he gonna eat now???
I'm not sure you need to go all the way back to the "breeder net live brine training method" (page 2 in the first 40 pages of this split thread, half way down the 2nd post) ...if he'll take frozen mysis, well, he'll take frozen mysis and I think the "movement" factor could easily be overcome because the thing SMELLS right and LOOKS right, he may fast for a little while but hunger should get him over the "movement" hump.
I know it sounds scary, but try the feeding station now....he may not "pick up" on it right away, but as long as you don't have other fish that are "pickers" when feeding, the food will just sit there uneaten until he finds it. There's a lot of info on feeding stations for Seahorses, I actually started with Melev's Mandarin Diner method (google it) but found solutions I liked better amoung the seahorse crowd (i.e. I didn't like the jar in any way shape or form, but if you have pickers sharing the tank, you'll need to go the jar route).
Basically, add some food in the morning, and if it's still there in the afternoon, remove it, and add some fresh. Hunger and natural "curiosity" should help him find the feeding station...a few weeks of only finding food there should get him "hooked". From there, simply introduce new foods with existing foods, or try a fast followed by the new food in the familiar setting.
All in all, if your mandarin is eating frozen, I think the hard part is over. Just keep in mind that EVERYTHING with adjusting mandarins seems to be a slow process of weeks or months. I posted a poll somewhere asking how long folks had maintained mandarins...it seemed that for a larger part it was either less than a year or 5 or more. Don't know what their natural lifespans are, but I think I've broken the year mark and then some.
Of course, with all of this comes the caveot of being prepared for an uncooperative mandarin...watch for the telltale signs that problems are arising (i.e. flat or concave belly, that long "Rib spine" starting to show as that protruding bony line running down their laterals etc...
One last thought regarding your intial question - "So from what you said teh only way to keep a pair, letalone two in a small tank, is too feed a lot?" - YES. I'm not happy until my mandarins are FAT like little sausages (someone wrote that about mandarins somewhere and looking at my long-term residents, I'd say that's a GREAT description).
'Nite!
MP