What is the ideal diet for my crested gecko?
A: Feeder Insects
B: Fruit
C: Commercially prepared food (known as crested gecko diet or CGD)
If you’re looking at these choices and find yourself unsure, then you’re in the right place. We know there are so many conflicting opinions and misinformation all over the internet. We see countless questions like, “can crested geckos eat mealworms?” and “can geckos eat fruit?” but never definitive answers. Should they be eating more CGD than insects or vice versa? In fact, you could ask two different keepers and you’ll likely get two very different answers. Well, here at BRONA Herpetology, we aim to provide evidence-based guidance and ensure you feel confident feeding your crested gecko a diet optimized for his unique needs.
Let’s first remember that crested geckos (Correlophus ciliatus) are wild animals and we as keepers should make every effort to maintain good husbandry practices. Ideally, the diet provided for our animals should closely mimic that of their wild counterparts. In their natural habitat, their diet primarily consists of fruit, nectar, and insects1. Unfortunately, due to incomplete information regarding the nutrition quality of various fruits and insects and conflicting recommendations on the preparation of a fruit and insect diet, this dietary regimen is not commonly followed.
The hesitance to adopt a more natural diet based on invertebrates and fruit is not without merit. Crested geckos are prone to various nutrition-related diseases including metabolic bone disease (MBD) which is preventable by providing appropriate amounts of calcium, phosphorus, and vitamin D in their diet. When attempting to feed a diet with various insects and fruits that all contain unique amounts of these micronutrients, it can quickly become overwhelming to try to manage the micronutrient balance.
So what is a keeper, hobbyist, or breeder to do?
On one hand, you want to provide your animals with the most naturalistic diet possible but on the other, you want to ensure that preventable nutritional deficiencies are avoided. That’s where choosing and preparing natural food items appropriately becomes critical.
Fruits
Fruits must be nontoxic and contain a high calcium to phosphorus ratio. A list of suitable fruits includes2,3:
- papaya
- mango
- pear
- blueberries
- strawberries
- fig
Insects
Live invertebrates primarily provide protein and fat to the gecko so should be gut-loaded and calcium dusted to increase their nutritional value prior to feeding which is explained in more detail below2,3,4. Additionally, and quite importantly, including live invertebrates in your gecko’s diet provides enhanced enrichment by allowing her to use her hunting skills as well as allowing you to observe your animal exhibit some of its natural behaviors. A list of appropriate live feeder insects includes:
- Dubia roaches
- Crickets
- Locusts
- Black Soldier Fly Larvae
- Mealworms*
- Waxworms**
- Hornworms
- Silkworms
*Mealworms should only be given in moderation due to their harder outer shell as compared with other feeder worms. This shell can be more difficult for your gecko to digest and in worst cases could lead to a digestive issue called impaction.
**Waxworms should be fed as an occasional treat due to their high-fat content but are excellent for juveniles struggling to gain weight.
Gutloading and Calcium Dusting
Gutloading is a process where your feeder insects are provided a nutrient-rich supplement in the days before you plan to offer the feeder insects to your crested gecko. The gut-loading product should be high in calcium and ideally, will also provide protein, fat, and other micronutrients to your feeders making them much more nutritious for your gecko.
Calcium dusting is exactly what it sounds like. Take a few feeder insects and place them in a small cup or bag, add a small amount of calcium carbonate powder, and gently shake. This process further increases the calcium content of the feeder insect and by extension, increases the calcium to phosphorus ratio. As mentioned earlier, metabolic bone disease is a preventable disorder that is often caused by calcium deficiency so don’t forget this crucial step!
Commercially Prepared Diets
We cannot discuss crested gecko nutrition without exploring the plethora of commercial products available, commonly referred to as Crested Gecko Diet (CGD). These powdered diets typically contain a blend of fruits, protein, and micronutrients with or without added invertebrate meal. The idea is that they have been formulated specifically to include an appropriate amount of macronutrients (protein, fat, and carbohydrate) as well as the right blend of micronutrients (vitamins and minerals). Pros – they are convenient and easily accessible. They are relatively inexpensive and have a decent shelf life, especially if open bags are kept in the refrigerator. They take the guesswork out of creating a balanced nutrition plan for your animals. They remove the need for additional multivitamin supplementation3. Cons – they do not accurately reflect what a crested gecko would consume in the wild. Many brands, including top-rated ones, contain fillers that you definitely want to avoid such as rice bran and oat fiber. They do not encourage hunting behavior for enrichment. According to a study from California State University, juvenile crested geckos gained significantly less when fed CGD as compared to a diet of papaya and dubia roaches that were gut-loaded and calcium dusted which has important implications for growth and development5. Finally, an important note about CGD is that it is so ubiquitous in the community that most crested geckos you encounter have been raised on it and this is now the food source that they prefer to the point that many suggest it is the only thing they should be fed. Despite whether it is the “best” nutrition for your crestie, it may be the only thing she accepts.
Micronutrient Supplementation
Supplements are another area where owners may find the available information is at best unclear or at worst dangerous. Just like in humans, when it comes to supplements there can be too much of a good thing. Many preventable conditions in reptiles are related to either deficiency or overdosing of micronutrients such as vitamin A, vitamin D, or calcium6. The key is understanding what supplements your animal needs based on the diet she is consuming. If he is already consuming CGD as his primary or supplementary food source he does not need a multivitamin. If he is strictly on a fruit and insect-based diet you will want to consider a multivitamin with a few important points in mind. First, a multivitamin does not have enough calcium alone to replace the need for the calcium carbonate supplementation that will be dusting your feeder insects with, so as we discussed early, a quality gut-loading supplement and calcium carbonate for dusting live feeders remains imperative. Next, if your setup includes adequate UVB light, your gecko will be able to convert vitamin D precursors to active vitamin D and will not require vitamin D supplementation6. If she does not receive adequate UVB she will need vitamin D supplementation so you can either choose a calcium carbonate/D3 blend for calcium dusting or choose a multivitamin that includes vitamin D37. Conversely, your multivitamin should be free of vitamin D3 if your gecko is getting appropriate UVB exposure in his setup. Lastly, carefully follow dosing for your multivitamin product to avoid vitamin A in excessive amounts7.
Conclusion
Alright, if you’ve made it this far you’re now an expert in nutrition and feeding for crested geckos and I invite you to go back and consider the question at the beginning of this post, “what is the ideal diet for my crested gecko?”. Our recommendations based on our thorough review and understanding of the best available guidance and scientific research are to rotate feeds of high-calcium fruits (we love papaya), appropriately-prepared invertebrates, and utilize a filler-free CGD as a supplemental food source. Here’s our suggested feeding schedule:
- Invertebrates 1-2 times per week
- Fresh fruit daily for juveniles or every other day for adults
- Replace fresh fruit with CGD every 2nd-3rd week
It is important to note that if you have a gecko that is already habituated to a specific feeding regimen, they may not be interested in the new foods you try to introduce. It is important to have patience and be willing to try out different fruits and insects to find items that work for your crestie. Tell us about your feeding schedule and what fruits and insects your cresties like.
Resources
- Brusso, K. (2013). Rhacodactylus ciliatus. Animal Diversity Web. https://animaldiversity.org/accounts/rhacodactylus_ciliatus/
- RSPCA Crested Gecko Care Sheet. (2015). Royal Society for the Prevention of Cruelty to Animals. Retrieved June 12, 2022, from https://www.rspca.org.uk/adviceandwelfare/pets/other
- Love, C. (2012). Crested Gecko. Arbor View Animal Hospital. https://arborviewah.com/wp-content/uploads/2021/08/Crested-Gecko-Resource.pdf
- Royal Veterinary College, University of London. (n.d.). Crested Gecko Care. Reptile Vet Services. https://www.rvc.ac.uk/Media/Default/Beaumont%20Sainsbury%20Animal%20Hospital/documents/Crested-gecko-care%202016.pdf
- Atamian, S. (2020). The Growth Effect of a Commercial Diet versus Calcium-Dusted Blaptica dubia and Carica papaya on Juvenile Correlophus ciliatus. Federation of American Societies for Experimental Biology, 34(S1), 1-1. https://doi.org/10.1096/fasebj.2020.34.s1.02662
- McWilliams, D.A. (2006). Nutrition research on calcium homeostasis I. Lizards (with recommendations). International Zoo Yearbook, 39(1), 69-77. https://doi.org/10.1111/j.1748-1090.2005.tb00006.x
- Stahl, S. J. (2012). Nutritional Secondary Hyperparathyroidism. In J. Mayer & T. M. Donnelly (Eds), Clinical Veterinary Advisor: Birds and Exotic Pets. (pp. 121-125). Elsevier Health Sciences.