I agree with everyone else in here.
LIve worms are very addictive to rays, i know mine loves them, but i do mix up the food, i give him frozen squid (he loves this stuff), also give him frozen bloodworms, jack watley discus food, and also silverides. At first he wouldnt take the silverides too well, so i soaked a few in bloodworms and he ate them quite quickly. I am in the process of getting him on Hikari massivore dlite, (its going to take time with this food, but he is slowly eating them.)
Also, it does look like he is eating, if you look at his tail at the base where his body is, it looks a bit fat, that usually means he is putting on some fat,which is good. Mine has a fat tail at the base and i know he is eating.
Also like has been said, make sure to feed him after the lights go out, they hunt at night. I feed mine mostly at nite and early morning. Sometimes when the light is on, he still eats but is a litter slower getting it when the lights are on.
Hang in there, im sure he will be fine, as long as he eats something every day