Bangaii cardinal not eating?

hi i got i bangaii cardinal about 1 inch i have had him for 3 days he is not touching anything doesnt even look at it i have tried flakes brine mysis fresh squid octopus burramundi and marine dinner stuff i havent had him for long but should i be worried and what should i feed him and i know live food works but i cant get any foe 2 weeks please help oh and no fish are bullying him