For fish experts and/or top contributors, how do I get my new Zig Zag Eel to eat?

I got him the other day from Live Aquaria and all he does most of the time is hid in this cave ornament I have with his head poking out but stays buried in the sand where I cant see him. I read they can eat bloodworms and earthworms but I got flake food and sinking pellets as well too. Whenever I put any food in the aquarium I never see him come out of hiding to eat anything and it kinda worries me some. He is about 5 or 6 inches long by the way.