Fuel, it's only your spotted mandarin that's taking to frozen foods, right? Further, it's in a controlled environment. In tanks with other fish, the timid mandarin wouldn't stand a chance competing with other fish for frozen foods such as mysis.
I am sure it's not your intention to mislead reefers (esp newbies) into thinking that it's possible to keep a mandarin alive/healthy in captivity with manual feeding by sharing the preliminary results of your 'experiment'.
Hence, as Damien shared earlier and as a general guide, Mandarinfish/Dragonets should only be introduced into a well-seasoned aquarium that is at least 6 mths old with plenty of microorganisms and other animals (e.g copepods) found in live rock and live sand. There should be at least 20-30kg of cured quality LR. Only 1 mandarin should be kept per tank. However, 50-60kg of quality LR may be able to sustain 2 mandarins.