What do you feed your hermit crabs?

I bought a hermit crab for my daughter when we went to the beach this weekend. I’ve read on many different websites that they can eat just about anything that we humans eat.

This website states that hermit crabs like all kinds of fruit, meat, fish, and tree leaves. I just cut up a grape for the little guy and put it in his cage but he’s not touching it. I know you can’t force feed a crustacean obviously but I want to know if anyone has hermit crabs that have a favorite treat. =]