I would be kinda hesitant to put anything wild into their tank if it's not from where they came out of. I hear that a good food item is algae wafers, the kind that you feed to algae eating fish like plecostomus. my tadpoles enjoyed these, you just hafta make sure to clean up any uneaten debris. Also my leopard frog tadpoles LOVED the frog n' tadpole bites, bought at a local pet store. they went nuts for them.