Free-living house geckos (Hemidactylus spp.) have broad diets and consume a variety of small invertebrates. In captivity, they thrive on a diet of commonly available, commercially produced insects, such as crickets, mealworms and roaches. It is important to gut load all feeder insects before offering them to your gecko. Consult with your veterinarian to determine an appropriate vitamin and mineral supplementation schedule.
Try to offer your gecko a variety of different prey, to help ensure he receives a balanced diet. In addition to crickets, mealworms and roaches, house geckos may consume wax worms, earthworms, red wigglers, silkworms or small super worms. In all cases, be sure to offer your pet suitably small food; feeders should be no longer than the width of your gecko’s head. Hatchling house geckos require very small food, such as flightless fruit flies or pinhead crickets.
Wild Caught Insects
In the interest of dietary variety, some keepers like to supplement their lizard’s diet with wild caught insects and invertebrates. While your gecko likely will consume appropriately sized grasshoppers, moths, slugs and beetles with gusto, these foods may carry and transmit parasites. Use caution to avoid collecting insects from areas that have been treated with pesticides and other chemicals. Never feed your gecko stinging insects, such as bees or wasps, or insects that produce noxious secretions, such as stinkbugs or ladybugs.
Never feed your gecko lightning bugs, as they are fatally toxic to some lizard species.
Before you feed any insect to your lizard, put them in a temporary cage and feed them a high-quality diet -- a practice called "gut loading." This will fill the insects’ guts with vitamin-rich foods, which will help keep your lizard healthy. Give the feeder insects a dish of oatmeal, plenty of dark leafy greens, a few carrot slices and an orange slice. Allow the insects to feed on the foods for 24 hours before offering them to your gecko.
In addition to gut loading your feeder insects, it is helpful to provide your lizard with a vitamin supplement to ensure he remains healthy. Most such vitamins come in powdered form, and you can administer them by coating the feeder insects in the powder before offering them to your lizard. It is important to avoid oversupplementation. Consult with your vet to determine an appropriate regimen. In addition to vitamins, your veterinarian may recommend offering supplemental calcium to young geckos and mature females.