honestly bro, i'm not sure ... just by chance.
i got these from a fellow reefer who decommed quite some time ago. they ate frozen mysis and actually saw them do. but when i introduced them to my tank, they starting eating pods, and however i tried later on didn't mind frozen mysis. since my nano didn't have much pods (and that's the reason i got this mandarin pair as they ate frozen) i resorted to trying out live brine. good thing is they willingly did, so problem solved before they go starving. i also replenished my tank with tigger pods. from then on my mandarin's became fat. i since have a small plastic tub aerated which holds my live brine stock for up to 5 days.
one thing about brine is specially at maturity, they actually lose their nutritional benefits. also, when i load up the brine and tiggers, my selfish clowns especially would consume most of it. the tiggers tens to 'swim up' and they chew them up like nuts. my mandarin's would move like a heat-seeking rocket on these live food, but VERY SLOW ... lasts up to 10 seconds, and by the time they're about to peck on it ... swoosh, intercepted by the clowns !
so i then started feeding pellets first so all others would get their tummies full before laoding up live feeds. at one time quite some pellets landed around the mandarin, and he just started pecking on them, to his liking that he ate a lot, later on to throw up ! then eat again ... since then he's been eating these pellets, spirulina, LPS food ... mysis, still no.