Leopard geckos are insectivores. They will feed upon just about any appropriately sized insect. Crickets are the most popular food choice for captive geckos. They are readily available and quite inexpensive, if purchased in large quantities. Cockroaches are becoming an increasingly popular food choice for leopard geckos. These feeder insects need be no larger than three-quarters of an inch before being fed to your pet. Both crickets and cockroaches should be gut-loaded with things like lettuce, orange slices, and dry dog food to provide your gecko with the most nutritional value.
Since leopard geckos are nocturnal, they should be fed at night, and uneaten food should be removed in the morning. Never feed your leopard gecko more food than he can eat in one sitting.
Leopard geckos are almost always very easy to feed in captivity. If your leopard gecko is refusing to eat, he may have a significant health problem. If possible, take him to a reptile veterinarian as soon as possible.