That is awesome to hear you have a thriving mandarin! I just love the mandarins more than any other fish.
Well, I had a plan in mind but that seems to have changed. Originally, I'd planned to very, slowly and carefully build up my copepod population in the tank before adding a mandarin. After reading tons of info and various opinions, I created a "pod pile" with rubble and shells in the back of the aquarium and also removed the bio-balls from the middle chamber and replaced those with live rubble rock too. I purchased a couple bottle of those TiggerPods and dumped them into the main tank and the back chamber, hoping to kick start a population. Also, since keeping a mandarin is my goal, I steered away from other fish that graze on copepods, like the wrasses.
Then enter my trip to Dallas and the equivalent of a saltwater Disneyland

I kid you not, the store had a tank full of mandarins....and they all were eating live brine. Supposedly this is uber rare to find a mandarin that will accept other live foods. I stared in disbelief and spoke with one of the fish store guys who said their mandarins all eat live foods. I was still skeptical at which point another shopper walked by, obviously a regular customer, and she started talking about how much she just loves her mandarin that she bought from them. She started off with 2 in a 10 gallon nano (????) and they ate whatever she threw in. Just recently she upgraded to a twenty something tank and moved them and they are still thriving. Okay, I was still skeptical and asked how long she'd had them. Over a year! The fish store guy then led us over to one of their medium sized display tanks and pointed out a huge male and several females. He said that they had all resided in the tank for a long time and that they were starting spawning behavior. Sure enough, the females were big and round.
(sorry for such a long story but it was just such a surprising experience)
Needless to say, I walked out of that store with a mandarin. I picked a large male, who was very nice and fat looking. They fed the tank while we were there and this guy swam around with zeal chasing the brine shrimp. From all that I've read, it seems like luck has a lot to do with successful keeping and a majority of the battle is finding a healthy, eating specimen to start with. I just couldn't pass up the opportunity.
Anyhoo....his name is Beemer

He's been in my 29g for a couple weeks now. So far I've had success feeding him live brine, frozen brine, frozen bloodworms, and the tiggerpods. He will not eat Arcti-pods or the Cyclopeeze which cracks me up because both state they are they ideal food for picky eaters like mandarins, sea horses, etc. I've started a copepod culture tank, 6.6 gallons, and have various species hopefully breeding (I just set it up this week). So far he is looking great, very active....cruises around the rocks all day picking away, not at all shy. At feeding times he's already found the best corner in the tank to get the food and goes right to the spot as soon as food hits the water and I watch him eat the food from wherever it lands, on the sand, on the rock, floating near this surface...he doesn't seem to care.