A balanced diet is the cornerstone of reptile health — yet it's one of the most common areas where keepers, especially beginners, get it wrong. Each species has unique dietary requirements, and feeding a generic "reptile diet" can lead to malnutrition, obesity, or even life-threatening metabolic disorders. Here's what you need to know.
The Three Main Diet Types
Reptiles fall into three broad dietary categories:
Carnivores / Insectivores These reptiles eat animal protein — primarily insects, but some species also consume rodents, fish, or other small animals.
Examples: Leopard geckos, bearded dragons (juveniles), snakes, chameleons, monitor lizards Key Nutrients: High-quality protein, calcium (with D3), fats, vitamins A and E
Herbivores These reptiles eat plant matter exclusively — leafy greens, vegetables, fruits, and flowers.
Examples: Tortoises (most species), uromastyx, green iguanas, chuckwallas Key Nutrients: Calcium, fiber, vitamin A, low protein
Omnivores These reptiles eat both animal and plant matter, with the ratio shifting as they age.
Examples: Bearded dragons (adults), crested geckos, box turtles, blue-tongue skinks Key Nutrients: Balanced protein and plant matter with appropriate calcium supplementation
Feeder Insects: The Foundation of Carnivorous Diets
Not all feeder insects are created equal. Their nutritional content varies dramatically based on what they've been fed (gut-loading) and how they're raised.
The Best Feeder Insects
Crickets: The standard feeder. Good protein content but low in calcium. Must be gut-loaded and dusted. Noisy, can escape, and have a strong odor.
Dubia Roaches: The gold standard for reptile feeding. High protein, excellent calcium-to-phosphorus ratio, quiet, odorless, and cannot climb smooth surfaces or fly. Easier to keep as a colony than crickets.
Black Soldier Fly Larvae (Phoenix Worms / Calciworms): Naturally high in calcium — no dusting required. Small size makes them excellent for young reptiles and small species.
Mealworms: High in fat, low in calcium. Best used as a treat or for species that need higher fat content. The hard exoskeleton can be difficult for some reptiles to digest.
Superworms: Larger, more nutritious versions of mealworms. Good for adult reptiles but still high in fat.
Hornworms: Very high in moisture and calcium. Excellent for hydration and as a treat. Grow quickly and can be expensive.
Silkworms: Exceptionally nutritious with a perfect calcium-to-phosphorus ratio. One of the best feeders you can offer, but harder to source and more expensive.
Gut-Loading: You Are What You Eat
Feeder insects are only as nutritious as their last meal. Gut-loading is the process of feeding your insects a nutrient-dense diet 24–48 hours before offering them to your reptile.
Best Gut-Loading Foods: - Commercial gut-load diets (e.g., Repashy Bug Burger, Fluker's High-Calcium Diet) - Fresh vegetables: sweet potato, carrots, collard greens, squash - Fruits: oranges, apples (in moderation) - Oats and wheat bran
Dusting: Calcium and Vitamin Supplementation
Even gut-loaded insects lack sufficient calcium for reptiles. You must dust feeders with a calcium + D3 supplement at most feedings, and a multivitamin 1–2 times per week.
Dusting Schedule: - Calcium + D3: Every feeding for juveniles and gravid females; 3–4 times per week for adults - Multivitamin: 1–2 times per week - Calcium without D3: On non-D3 days if using UVB
Greens and Vegetables for Herbivores and Omnivores
Staples (Feed Daily) Collard greens, mustard greens, turnip greens, dandelion greens, endive, escarole, kale (in rotation), spring mix
Secondary (Feed 2–3 times per week) Butternut squash (shredded), zucchini, bell peppers, carrots, snap peas, okra
Fruits (Treats only — 1–2 times per week) Berries, mango, papaya, melon, figs, banana (very high in sugar)
AVOID these foods - Spinach and swiss chard (high oxalates bind calcium) - Rhubarb (toxic) - Avocado (toxic) - Iceberg lettuce (no nutritional value) - Citrus fruits (too acidic for most reptiles)
Feeding Schedules by Age
| Species Type | Juvenile | Adult |
|---|---|---|
| Bearded Dragon | Insects daily + greens | Insects 2–3x/week + greens daily |
| Leopard Gecko | Insects daily | Insects 3–4x/week |
| Crested Gecko | CGD daily + insects 2x/week | CGD daily |
| Corn Snake | Mouse every 5–7 days | Mouse every 7–14 days |
| Russian Tortoise | Greens daily + calcium | Greens daily + calcium |
Signs of Poor Nutrition
- Soft or misshapen jaw (metabolic bone disease — calcium deficiency)
- Lethargy and weakness (malnutrition or improper temperatures)
- Poor shedding (humidity or vitamin A deficiency)
- Swollen limbs or joints (gout from excess protein)
- Weight loss or obesity (improper feeding schedule)
- Sunken eyes (dehydration)
Hydration
Fresh, clean water must always be available. Additionally:
- Mist tropical species daily to provide drinking water from leaves
- Soak tortoises 2–3 times per week in shallow, warm water for 15–20 minutes
- Monitor for dehydration: Loose, wrinkly skin and sunken eyes are warning signs
The Golden Rules of Reptile Feeding
- Variety is key — No single food provides all necessary nutrients.
- Calcium-to-phosphorus ratio should be at least 2:1 in favor of calcium.
- Gut-load your insects — It doubles their nutritional value.
- Dust properly — Calcium at nearly every feeding for growing animals.
- Feed appropriate sizes — No larger than the space between your reptile's eyes.
- Remove uneaten food — Crickets bite sleeping reptiles; rotting food breeds bacteria.
Feeding your reptile properly takes knowledge and consistency, but the reward is a vibrant, active, long-lived companion. When in doubt, research your specific species' dietary needs and consult with an exotic veterinarian for personalized advice.