I have one of my original mandarins, the female, she has been in my tank for at least 9 years now. The male jumpped into the overflow couple years ago. They were together for a long time and spiralled and spawned sometimes.
This mandarin has never eaten anything I put into the tank. Have never seen it show interest towards frozen mysis or pellets. It's not crazy fat like some I have that do eat frozen but she is naturally healthy. I do not add pods to this tank ever.
Makes me wonder. Does the fact that some eat foods keep them from starving, yet those that do not eat frozen or pellets and only eat natural live foods at their own pace live longer.
Overall they are not difficult fish to keep. Folks just need to be aware of what their diet is and make sure their aquariums are producing it.