Feeding Iguanas

By Laurie Hess, DVM; Rick Axelson, DVM

An improper diet contributes to many health problems in iguanas. Over the past 20 years, veterinarians have learned a lot about proper nutrition for reptiles, so the recommended diet for pet iguanas has changed a great deal.


What should iguanas eat?

Iguanas are herbivorous, meaning they eat plants; specifically, they are folivores, meaning they eat leaves. In the wild, iguanas feed almost entirely on the leaves of trees and vines, plus some fruits and flowers. As hindgut fermenters, iguanas have specific microbes (special bacteria and flagellate organisms) that normally inhabit their gastrointestinal tracts to ferment the high-fiber foods they ingest, so that nutrients in their food can be absorbed in their intestines and used by their bodies.

"In the wild, iguanas feed almost entirely on the leaves of trees and vines,
plus some fruits and flowers."

While most veterinarians recommend feeding only plant material to iguanas, many others feel that supplementing the total diet up to 5-10% with commercial canned or pelleted food formulated specifically for iguanas is acceptable.

How often should I feed my iguana?

Most young iguanas need to eat daily, while adult iguanas can be fed daily or every other day if they are overweight.

What types of plant material I can feed my iguana?

Most of the diet (80-90%) should be dark green leafy vegetables, with less than 20% of the diet as fruits. Yellow, red, and orange vegetables also can be offered. Avoid nutrient- and vitamin-deficient light green vegetables, including iceberg or head lettuce and celery, as these vegetables contain mostly water and few nutrients.

Calcium-rich vegetables that are best for feeding iguanas include collard greens, beet greens, mustard greens, turnip greens, alfalfa hay, bok choy, kale, parsley, Swiss chard, romaine, kohlrabi, escarole, and dandelion. These vegetables should make up 40-50% of an adult iguana’s diet, Other vegetables, including cactus, broccoli, squash, bell peppers, green beans, sprouts, sweet potato, parsnips, okra, cucumber, asparagus, mushrooms, carrots, peas, and corn can make up an additional 30-40% of an adult iguana’s diet.

"Most of the diet (80-90%) should be dark green leafy vegetables,
with less than 20% of the diet as fruit."

While Swiss chard, spinach, and beet greens are a great source of calcium, they should not be fed exclusively. These plants contain oxalates that can bind to other sources of dietary calcium and trace minerals, preventing their absorption in the intestine, thereby making them unavailable to the lizard, potentially leading to nutrient deficiencies. In addition, cabbage, kale, and mustard greens contain goitrogens (chemicals that can lead to goiter, or hypothyroidism, in which the thyroid gland becomes enlarged and  functions improperly); therefore, these vegetables should be fed only in small amounts.

Fruit should make up only a small percentage (less than 20%) of an iguana’s total diet. Fruits that may be offered to iguanas include apples, pears, bananas (with skin), mangoes, grapes, star fruit, peaches, tomatoes, guava, kiwis, melons, figs, apricots, dates, blueberries, raspberries, and strawberries. Since iguanas love tasty fruit, and most fruit is water-rich and nutrient-poor, these items should be fed sparingly as top dressing on vegetables. As a treat, edible flowers such as geraniums, carnations, dandelions, hibiscus, nasturtiums, and roses, may also be offered to iguanas. Finally, young growing iguanas also may be fed legumes, including boiled lentils, navy beans, pinto beans, kidney beans as up to 5% of their total diet.

Vegetables can be offered cooked or raw, although raw is preferable, since cooking removes many essential nutrients. Thoroughly wash all fruits and vegetables to remove all debris and pesticides before feeding them. If available, organic produce, grown without pesticides or other potentially toxic chemicals, is best to feed to your pet iguana. Edible flowers can be home grown or purchased from floral shops. Often, floral shops throw out older, wilting flowers that iguana owners can often get at no charge. Be sure that no chemicals have been applied to the flowers before feeding them to your iguana.

Are animal-based protein foods appropriate for my iguana?

In general, foods comprised of large amounts of animal-based protein, such as crickets, mealworms, pinky mice, tofu, and hard boiled eggs, are too high in protein for iguanas to eat frequently and should be offered as less than 5% of the adult iguana’s total diet. Young, growing iguanas can have up to 10% of their total diet made up of animal-based protein sources. Dog and cat food contain too much protein, vitamin D, and fat for iguanas and should not be fed regularly.

Do I need to give my iguana vitamin and mineral supplements?

The amount and type of supplements required by iguanas is controversial and somewhat age dependent. All iguanas, regardless of their age, have a higher requirement for dietary calcium than phosphorus. Most veterinarians recommend lightly sprinkling a growing iguana’s food every other day (4-5 times per week) with calcium powder, specifically formulated for reptiles (calcium carbonate or gluconate), without vitamin D or phosphorus.

There is some controversy over whether iguanas are able to absorb vitamin D from their food (they may only be able to use the specific form of vitamin D made in their skin in response to UV light). However, since young, growing iguanas need vitamin D to form their bones properly, and many are housed inside with minimal UV light exposure, most veterinarians recommend that young iguanas receive a multivitamin supplement containing vitamin D twice a week.

"Any supplements should be dusted onto small portions of salads or moist foods and those portions fed first to ensure that the iguana receives them."

While recommendations for supplementing adult iguanas vary, most veterinarians recommend that adult, fully grown iguanas should be given a calcium supplement lightly sprinkled on their food once to twice per week and a multivitamin containing vitamin D twice a month. Any supplements should be dusted onto small portions of salads or moist foods and those portions fed first to ensure that the iguana receives them.

Check with your veterinarian for specific recommendations for supplementing your pet iguana's diet.

Does my iguana need water?

Fresh clean water should be available at all times for your iguana. Iguanas will not only drink from the water bowl, but also bathe in it. Since reptiles absorb water through their skin, both drinking and bathing help keep iguanas hydrated. Provide water in a heavy bowl that is not easy to tip over. Change the water and clean the bowl daily, as iguanas often will eliminate in their water bowl while bathing. You should also mist your iguana with a water sprayer a few times a week to help keep him stay hydrated, especially during the winter when the air is colder and drier.

Opinions vary regarding the nutritional needs of captive iguanas, and our knowledge in the subject is continually expanding based on new dietary studies in reptiles. Therefore, if you have a pet iguana, you should discuss your pet’s specific nutritional needs with your veterinarian at each wellness visit or annual examination.

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