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Green Iguana Care Guide - The Critter Depot

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Table of Contents

Green Iguana Care Guide

iguana care guide

Table of Contents

Introduction to Green Iguanas

These creatures are the mood rings of the reptile world. Yes, they are generally green, especially those from central America as opposed to the browner Mexico locales. But this can change with mood, environment and health. A brilliant green is not necessarily the happiest or healthiest of iguanas, but it might be! Part of the fun and challenge of this species is knowing their individual personalities and needs, and no two are alike.

Adult males grow to approximately 6-7 feet in length and adult females are two thirds that size. These diurnal (active during the day) reptiles, enjoy spending their days relaxing in shrubs and trees basking in the sun.

Although not the longest living of reptile pets, given optimal care, green iguanas can live an average of 15 years. While they will definitely fight among themselves if housed together (no advised) they are rarely aggressive toward human keepers, in fact, just the opposite. They can defend themselves against aggression with a toothy bite. But generally, given half a chance, they become very fond of their keepers and will eagerly swarm all over them for a tasty handout such as romaine lettuce or a hibiscus flower.

Green Iguana Habitat

This is a really large lizard at maturity and as such needs a really large habitat. So be prepared to fork over some money for the right one. Many keepers devote an entire table to the cause. Folding tables are not recommended, as the final habitat set up will be rather heavy.

Young iguanas can be kept in something like an Exoterra 36" x 18" x 24" tank for the first 6-8 months of life. A tank or enclosure of this size will be sufficient until your iguana is about 1.5 feet long from snout to tail tip. But as they grow into adults, they will need a much larger living area.

iguana habitat set up

An adult male iguana is going to need a cage about 8 feet long, 3 feet wide, and 6 feet high, at a minimum. Since cages this large aren’t usually commercially available, you may have to build your pet a custom abode. A habitat can be relatively easily built with 2 x 4s, wire mesh, and plywood. If you are not handy, then some pretty spiffy cages can be acquired online from manufacturers such as Carolina Cages. But be prepared to shell out around $400 for a cage that will suit a juvenile or a mature female (maybe). But once your iguana reaches the ripe age of 4, you should expect to replace it again. Cruising YouTube videos made by and for green iguana owners is a great way to get an idea of what is out there for sale as a kit, or even plans for how to make one yourself.

Interior Design

Designing the perfect interior for your iguana can be fun once you have the right sized enclosure. It helps to think like an iguana as you get started.

  1. What would be fun to climb on?
  2. What would be comfortable to bask on?

Then proceed to plan the branches, plants, and ledges your iguana will enjoy.

You may have to try a few approaches to see what works best for your iguana within the habitat you have created. Remember to plan all of this well in advance of acquiring an adult pet, and also be prepared for a possible remodel once they are in residence.


For substrate, you want something that holds humidity well, like Zilla Jungle Mix or Zoo Med Eco Earth. Or, a more cost effective plan might be to concoct your own ‘orchid bark’ mix. No, this is not material made of orchids (and that would certainly not be cost effective) but rather the formula for growing Phalaenopsis and other species of orchids indoors. Here is a popular recipe:

  1. Begin with ground coastal redwood bark
  2. Add an equal portion of ground Douglas fir bark
  3. Add 1/3 as much Osmunda tree fern fiber. Soak this in water for about 12 hours first before you mix. All these materials are coarse, and they allow air to circulate naturally throughout the substrate until smashed down by the iguana over time. The tree fern fiber is great at retaining moisture.

Aromatic woods such as pine and cedar should be avoided as they can cause lung and eye irritation. A 2-3 inches covering of bark substrate provides a sanitary, attractive, and moisture laden bedding. Something to keep in mind regarding substrate is that environments with high ambient humidity (such as Florida) can saturate the earth substrate too much. This can create a breeding ground for bacteria and fungi. In these situations, the recommended substrate would be astro-turf or a similar product instead.

Further, some keepers with really large iguanas warn against the risk of impaction with a loose substrate of any kind. Instead, many recommend flat, round cobbles on top of a tile surface. With a substrate such as this, even the largest iguana who samples his environment with his tongue will not be able to inadvertently snag particles of substrate which over time can lead to gut impaction. It is harder to keep the humidity up and not have standing water with this substrate, however, so keepers in the dry regions of the country may need to experiment with substrates to find a happy medium.


Provide your iguana habitat with a basking spot with a temperature of 87 to 95 degrees Fahrenheit and an ambient temperature of 78 to 86 degrees. This is a very tropical species, at home in the steaming jungle, so don’t assume it’s warm enough just because you are. Keep their habitat warm, but not blistering (of course).

It is also important to give your iguana a choice.  Most keepers provide heat on one side only and not under the water bowl, so the iguana can either bask or chill, as the mood strikes. Most experienced keepers recommend an undertank heating mat under ½ the tank and placement of the water bowl on the other side. This arrangement is the most safe and sanitary, especially for night time usage when the basking lamp should be turned off.

Speaking of blistering, a basking lamp must be carefully placed so that it can never exceed 95 degrees F at the closest possible point to the iguana. There must a barrier, preferable mesh or screen (not glass so as not to amplify the heat too much), between the top of the cage and the heat lamp. Three inches of clearance between the iguana’s shoulders and the mesh when they are at rest is required to prevent burns. As your pet grows, do not forget to lower the perch proportionately.

It’s important to take readings at the surface of the bottom of the warm side, the cooler (water) side, and any basking areas. For temperature measurement, a digital laser thermometer can be quite handy. For less than $20, a new keeper can take readings from all over the habitat with the push of a button. Keepers need to remember that the ambient temperature of the room can affect the temperature of the habitat, so frequent readings are strongly recommended.


An average humidity of 75% is needed. It can be challenging to keep the humidity up in a habitat with a screen top. There are ways to accomplish this. Some are more labor intensive than others, but it is up to the individual keeper’s preferences and life style. Having a mostly solid top on your iguana’s habitat is the best way to ensure a steady, muggy atmosphere that your iguana will love.

Although the humidity level throughout even large habitats will be more consistent than temperature gradients, a hygrometer attached to the side of the enclosure will nevertheless take the guess work out of managing humidity. A successful keeper never assumes that once temperature and humidity provisions seem optimal, they will always stay that way. That is seldom true, and good monitoring of the conditions with changing seasons will prevent problems.

The tank needed for an adult green is so large that there is generally plenty of room to add a humidifier right inside the tank. There is a great deal of debate in the reptile keeping community about the best humidifier systems. The debate is not about the usefulness of having one, it is about hot versus cool steam. Everybody agrees that under most circumstances, in most regions, and especially in winter in overly dry and overheated buildings, warm would be ideal.

In summer, opinions are more divided. Some keepers have managed to find a small humidifier that emits a pleasantly warm steam, such as that sold by Sharper Image, and they swear by it. Others prefer the safety of a cool mist for safety reasons. Sanitation is easier, sure, but the opposing faction would claim that the iguana is less comfortable confronted with a cool spray, which may be true. Hence the debate.

My solution has been to convert a small room to a winter retreat/herpatarium that is like a down-scaled sauna. All of the walls have been painted with a high gloss paint (no Kilz, it is toxic) for moisture control. In winter, I keep that one room really humid compared to the rest of the house, and I keep the temperature up. While the rest of my western Colorado home is heated to 64 degrees F and the humidity is around 20%, the herpatarium is a balmy 74 degrees with an ambient humidity of 60%. I still mist my more tropical friends (with warm water), just to be sure, and then I relax in the middle of the room in a comfortable chair and breathe in that Caribbean-like ambiance. This makes the herps happy and prevents me from getting frequent nose bleeds.

I use a larger humidifier, which is appropriate inside an enclosure. In mid-summer, I throw open the windows scrub and repaint the slightrly mildew walls. This is just one of many approaches to providing adequate humidity and warmth for your reptiles and amphibians. And depending on the size of your dwelling and your geographic region and lifestyle, exploration with various options and experimentation with various products may be necessary.

Lighting for Iguanas

iguana basking

Many lizards do not need regular exposure to UVB light. The green iguana is not one of those. Direct sunlight is actually the best option, but many apartment dwellers cannot provide a separate outdoor sunning cage for their iguana.

Because of the size of the required habitat, this is one pet species that can be offered natural light at some portion of it’s enclosure for a portion of the day. Full sunlight on a large glass tank will indeed turn it into a solar oven, so a bit of commonsense is called for, such as turning off the basking light. If you are in the position to offer your pet direct sunshine through mesh or glass for at least 3 hours per day (including winter), then supplemental reptile lighting is not required.

My herpatarium room is on the north side of the house, so plainly supplemental lighting is necessary. This is a judgement call that each owner must make. I know some keepers who have a screened in porch in a very temperate area, and no supplemental interior reptile lighting is provided, just ambient house light. This method works well in Santa Fe, less so in New Hampshire. Consulting with other keepers in the immediate vicinity is often the best means of preventing health mishaps.

If your pet will not have access to bright sunlight, a special light will be required to provide the UVB wavelength. Referred to as ‘black lights’ they are readily available through many pet supply outlets. This is NOT the same kind of black light used for psychedelic experiences (Oh wow man, bummer). It is a source of light in the 290-320 nanometer range. Zoo Med's reptile lights, and Durotest's Vita-Lite are two good products. These UVB light sources should be replaced every six months.

When installing the light, remember that UVB light penetrate glass poorly, so the top of the enclosure directly beneath the light must be a wire mesh that is not so fine it acts as a shade cloth. Therefore, this is the one portion of the top of the habitat that should not be solid. There are many choices of lights, some of which need to be very close to the animal and some, such as mercury halide lights, can be effective up to 3 feet away.

Although this light source will permit your iguana to produce Vitamin D, useful for healthy bone development, it is not a complete substitute for a vitamin and mineral supplement. Speaking of nutrition…

Iguana Diet and Feeding

Best Foods to Feed Iguanas

Green iguanas are strict vegetarians. Foods recommended for them are:

  • Leafy Greens — Leafy greens will be a staple for your iguana, within reason. Although highly nutritious, certain greens are high in oxalic acids that can cause renal failure, while others are high in goitrogens that can interfere with the thyroid gland’s proper functioning. Recommended greens are:
  • Collard greens (low in oxalic acid and goitrogens
  • Mustard Greens
  • Escarole
  • Romaine
  • Turnip greens
  • Dandelion greens
  • Squash (all members of the cucurbit family are a good choice, just be sure to cut into small chunks):
  • Acorn
  • Butternut
  • Zucchini
  • Patty Pan
  • Cucumbers
  • Fruit
  • Stone fruits such as plums (stone removed), 
  • Bananas,
  • Figs (in moderation),
  • Melons,
  • Apples,
  • Pears,
  • Pineapples, mangos, papayas and even guava.
  • Iguanas also enjoy berries such blueberries, raspberries, mulberries and strawberries. The larger berries must be cut into chunks no larger than ½ the width of the iguanas mouth to prevent choking.
  • Flowers - Edible flowers such as:
  • Nasturtiums,
  • Hibiscus,
  • Dandelions,
  • Carnations
  • Bougainvillea
  • Roses. Note: Roses are a favorite treat, but don’t place that bouquet of wilting roses from the florist in with your pet. Flowers produced for the commercial floral trade may have been treated with any number of over 100 toxic substances. This means that handling these flowers has long term health consequences for the florists and deadly consequences for your pet. Only feed flowers that you are certain have never been sprayed with anything. If possible, grow your own.

Avoid These Foods

Kale and spinach should generally be avoided, as they are high in both compounds. Celery, beetroot, chard, fried potato chips, parsley and leeks, should all be avoided. Rhubarb leaves are highly poisonous as well.

Important Iguana Diet Supplements

Lastly, always make sure your pet’s food source has been dusted with a good source of additional nutrients. Calcium is probably the most important element in order to avoid the occurrence of metabolic bone disease. Calcium supplementation should be added to the food twice weekly and a multivitamin supplement every 2 weeks for adults, weekly for juveniles.

Regular dusting of food items with a supplement such as ReptiCal is most important for young iguanas - older animals that are closer to adult size need supplements less frequently. Whichever supplement you select, be sure that it includes a little iodine, since many of the leafy greens you will be feeding your iguana will tend to bind iodine.

Iguana Cleaning and Sanitation

Frequent cleaning of the tank is necessary because of the prodigious amount of poo that mature iguanas will put into the water. Spot cleaning of the substrate should be a daily task. Below is a proposed schedule for iguana maintenance:

  • Every day: Remove any feces that you see.
  • Weekly: Remove and dispose of the top 1 inch of bedding and replace with fresh material.
  • Bi-monthly: Place dishwasher safe furniture such as branches or basking platforms in the dishwasher every two weeks. Run on the pot-scrubber cycle.
  • Monthly: The fibrous substrate will need to be disposed of and then replaced with fresh. Any gravel bedding beneath the fibrous top layer can be soaked in bleach, dried, and re-used. All plants should be removed and the entire habitat sprayed with 10% bleach and allowed to dry for 2 hours. Do not use scented bleach. Plainly, during this time your iguana needs to be elsewhere, preferably basking safely in the sun. Be advised, if not monitored they can and will wander off. I have a friend in southern Utah who allowed her iguana to get away from her and she never got him back, although weirdly he was able to survive many winters and did just fine on his own, according to this lady’s former neighbors. Don’t let this happen to you, it may not have such a happy ending.

If the habitat has a glass side (which the front probably does), spray with vinegar after the bleach has been applied and removed. Wipe down again for better visibility. After wiping down, wait another ½ hour, install sanitized gravel and fresh substrate and reposition any sanitized furniture and plants. Then close it all up as usual and allow another hour at least for the humidity to reestablish and temperatures to come up to the required level before reinstalling your iguana.

Bathing iguanas are a very important part of their overall maintenance. Many keepers advise bathing your pet every day. If you are like me, that is not highly practical. I do mist twice a day, but only bathe my iguanas once per week.

How to Bath an Iguana?

I place my iguanas in the bathtub with one inch of water that is pleasantly warm to the touch (never over 90 degrees F). Just like a grade school slumber party trick where you put an early sleeper’s fingers into warm water to see if you can make them pee in their sleeping bag, my guys always poop in their bath immediately!

I then drain the tub and rinse it thoroughly, and then refill with 2-4 inches of water, depending upon the size of the iguana. It’s a bath, not a swimming hole, so even though I don’t leave the room with them in the tub, they must still be able to easily touch the bottom. I may multitask by cleaning something in the bathroom that needs attention, but I do not leave the room. This is therefore not a good time to clean the enclosure, even though it might be tempting.

Good sanitation and good nutrition are way more than half the battle to keep your iguana fit and healthy. Common sense and good information are useful as well, as is keen observation of your pet (after all, that’s why you have him/her, right?)

Happy Herping!


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