Imo, Unless you cultivate pods or have a very large tank with only 1 pod eater dragonets are not sustainable.
The best thing to do would be to train your Mandarin to eat frozen brine/mysis.
The way I've done it in the past is to use a hang on basket with a fine mesh and feed live brine for about 2 weeks. Sometimes it takes a few days to get them to even look at the live brine. Once they start eating those ill continue feeding them live for about 2 weeks and then slowly start mixing in frozen. 10% frozen for a couple days, 20% frozen for a couple days and so on until its eating only frozen. Then there free to go into the tank. It's still good to supplement live pods so they have stuff to pick at between feedings.
I've had a pair of mandarins for almost 2 years and I trained both of em that way. Don't be one of those guys who just throws mandarins in the tank and just hopes they'll survive.
In my opinion if your not willing to put in the time to train em then you shouldn't buy em.
