Male Kaudern's Cardinalfish not Eating

Hello. I have recently received a pair of Kaudern's Cardinalfish for L.A. I ordered 2 and they arrived in a bag togeather. I put them in the tank and they have stuck togeather for the past 2 days. My female will eat but my male will swim up to the food but won't open his mouth to eat the food. My Kaudern's Cardinalfish are living in a dead spot in my tank next to my heater. Is this behavior normal, how should I get him to eat?