What do baby toads eat?

Okay well my sister found a baby toad (its about the size of my thumb nail) 2 days ago and she has it in a little fish bowl and we dont know what it eats, we have some mulch and grass in the bowl. Do baby toads eat grass or like little bug? The toad is small so idk if it will eat a fly? What do most toads eat so we can feed him?