 Feed your tadpoles once a day with algae wafers and flake fish food from a pet store. Container life is stressful on tadpoles, so Johnson also recommends adding cover such as leaves for them to hide under. As they grow, you'll notice little buds that will become the rear legs. Add a rock or something to the bottom of the container so they can come up out of the water. Once the front legs develop, the tadpoles will stop eating.