What can I feed my fire-bellied toad?

I have 2 Fire-Bellied Toads and they have been fed crickets for 2 months now, but I read that your supposed to spice up their life a bit. I figured putting vitamins on the crickets and feeding the crickets apples and lettuce would be fine. But i decided to give them earthworms and pillbugs. So they threw up the pillbugs so thats a no. But they LOVE earthworms, yet I cant find anywhere that its ok/not ok so I am unsure. If their are other food options available that would be cool but I would also like confirmation that earthworms are ok... I get them from underneath my sons basketball hoop and also underneath our wooden deck. Thanks in Advance =D