In reality it's not terribly hard to train a mandarin to eat in a week or two.
I held mine in a Hagen breeder box (hob
) to keep it isolated & easily accessed. I started with garlic soaked brine to Mysis to garlic soaked Reef Pearls.
The breeder box gets water pumped in one side & overflows out the other. This keeps a slight current which keeps the food suspended & may make it more appetizing to the mandarin.
Without training, mandarins are a gamble. If you put the effort into training, you know it will eat prepared foods if it gets hungry enough.