I've caught plenty of tadpoles from the wild and never remember any of them dying, but I do have a lot of experience with "baby" animals. Having been a frog breeder for 6 years I can shower you with loads of information that may be useful. One thing to make sure to do is remove the new frogs from the container as soon as they are able and put them into a tank, because if not done soon enough, even after turning into a frog, they will die. Another good food source is seaweed. I gave this reguarly to my tadpoles and they loved it, and it seemed as if it made them stronger. You can find it in any Asian market place or section at your grocery store. If you have any other questions let me know.