+1 for CK, morays have horrible eye sight so they usually hunt by smelling around, soak some food in a garlic vitamin like GVH garlic soak, and see what happens. also, krill is not the best to feed it and there is better options than silversides too. I feed all my morays clams,squid,octopus,raw shrimp,scallops,etc.
since you haven't had him that long, he may just be on a "hunger strike" which in that case you need to leave him alone because putting food infront of his face only adds stress.