Hello and welcome to FF! You can feed all frog will eat until satiated. Some persons use a "all will eat in 15 min." rule; but my frogs eat fast and get full in couple minutes at most.

Food size should be distance between frog eyes. An excellent meal to alternate with crickets are night crawlers (available at Walmart's sport section). Since your frog is small, you can cut pieces of worm (from pointy end, it will heal up) and feed with plastic tweezers or drop in front of mouth. Earthworms are the perfect food for your frog. Do dust it's food 2X calcium and 1X vitamins weekly on different days with off day in between.

Once frog reaches around 3.5 to 4 in. it will eat lots and you might start noting it slightly less enthusiastic to start feeding on next day. That is signal to feed every couple days. A full grown frog can be fed a large meal on a weekly basis. Do read this excellent article for more information on your frog care: Frog Forum - African Bullfrog - Pyxicephalus adspersus - Care and Breeding and good luck .