As a tadpole, a frog will eat only algae. It will continue to eat small plants until it becomes a full developed frog. For people who own tadpoles, a good alternative to algae is lettuce that has been boiled and chopped up.
According to HowStuffWorks.com, a frog will eat just about anything it can catch as long as it is still alive. As a baby, most small frogs will only eat bugs, snails and even tadpoles. Larger frogs will eat mammals, birds, reptiles and fish. Frogs have the ability to quickly spot movement; once it notices moving pray, it tries to catch it. For frog owners, it is possible to feed their pets wingless flies or even worms.
Frogs do have teeth, but they don't use it to chew their food. Frogs grip their food with their teeth; if they like the taste, then they will swallow it whole. In the event that the frog doesn't like the taste of its prey, it will spit it back out of its mouth.Learn more about Frogs