My American toads at primarily night crawlers. They are pretty much the most nutritious and easily digestible food that you can give them. Just make sure that they're dye free (not dyed for fishing) and do not have chemicals. Mine occasionally got crickets but preferred night crawlers over anything. Make sure you're dusting with vitamins and calcium.
EDIT - And this is why I usually copy my post and refresh before I post it. LOL Carlos already has you covered!