Give your tadpoles an hour to eat and then completely clean the container after each feeding. Avoid using soap or cleansers in your tank. Remember to refill with treated water. As the front legs grow the tadpoles will no longer eat. At this point they will reabsorb their tail as a food source and the tail will appear to shrink.
Tadpoles undergo four remarkable changes that are easy to observe.
First they grow legs - back legs first and front legs last. Second, they slowly lose their tails. The tail shrinks as its material is used as food by the tadpole. Later, breathing with gills changes to breathing with lungs. Finally, the creature's diet changes from eating only plants to eating only live animals, such as insects.