I have to disagree that the key to success is prepared foods. I've said this a million times, but the problem with relying on prepared foods is that mandarins are grazers. they're always hunting and eating. prepared foods can be a great supplement, but unless you also have a population of pods or feed very, very heavily, there's still a good chance the fish will starve, particularly if there are any other fish in the tank to compete for food.
under the right conditions there are very few easier fish to keep. IMO, it's a shame that people are always looking for a workaround to try to keep them in small tanks.