While the dead copepods in Arcti-Pods are a good food source for manadarins, it's wise to have live copepods in the tank so that the fish has a consistent food source. You can also get mandarins to eat our TDO Chroma BOOST pellets. Most people use TDO Small for mandarins that are at least an inch long.
Some very good recommendations in this thread. We always recommend a large tank, >55 gallons, with plenty of rock for the pods to colonize. I have a captive-bred, Biota mandarin that does quite well in our 55 gallon tank. In addition to eating our Apex-Pods, which have populated the tank nicely, it also goes after our TDO Small on a daily basis. It's also a good idea to exclude other pods eaters like wrasses.
Hope this helps.
Best,
Chad