Depends on the size of the fat tail. Adults can easily eat large crickets. A good rule of thumb for smaller ones is....... no larger than half the length of the geckos head. Anyone correct me if I'm too far off. My male eats 6-10 large crickets every night or two. I have two small, 25 grams, females that will take that many 1/4 inch crickets per night. Hope this helps

Quig