Mandarin fish need an established tank. How old is yours and what sort of tank is it as far as rock, corals, and substrate? They constantly forage. And while there are some, or many, who say a refugium is nice to have it comes back to how the pods get from point a (refugium) to point b (the display tank). It isn't always so cut and dry in the flow and plumbing which gets us back to how old, mature, and established is the tank?
There are a few people here who have baby brine shrimp feeders and/or devices that may help. You would have to search has I do not have it handy. Also I didn't ask but must. Do you have any other fish that will compete for similar food? Wrasse for example? Two or more fish competing for similar food the slower one will starve. Wrasses are fast. The Mandarin not so much and has a very different foraging pattern.
I personally wouldn't recommend one without it being well into a year or more established and a healthy pod population. Said population needs time to balance out based on the nutrients in the tank and predators. Anything faster is asking for problems.
Pre-happy birthday. Sure it isn't want you want to hear but they are advanced fish due to their diet and feeding needs.
