Pajama cardinal fish please help

I bought yesterday a cardinal pajama and this morning i put some frozen food all my fish ate fine but my cardinal didn't eat at all i heard that nocturnal they eat at night?

 

If you have a fish that currently has ich, you really shouldn't be adding more fish till it has cleared up. It is just going to be showing up on any fish that you add to the tank. That being said, it is probably stressed from being added to the tank. What acclimation method do you use? The drip method is easiest on the fish. Hopefully it will start eating after it gets used to its new environment

 

It turned out that i don't have ich anyway but i heard he eats at night is this true?

 

how did you turn out not to have ich? that fire fish photo you posted clear does.

its common for newly added fish not to eat as they acclimate to their new home, its also during this period ich has the best opportunity to infect a host. i never owned a cardinal so not sure if its nocturnal or not but regardless of wether he is or not he (like most fish) can be trained to eat with all the others. be persistent with your feedings and he will pick up on it as well.