Housing Considerations: A standard 29 gal or 32 gal aquarium should be used to accommodate a juvenile iguana for the first 6 to 12 months. For larger specimens, an enclosure with a length of at least 2 times the length of the animal, with a width equal the length of animal and a height at least equal to the length of the animal will provide adequate living space. The substrate should either be bark chips or newspaper. Bark chips have the advantage of soaking up excess moisture while providing air humidity without a wet surface. Avoid gravel or fine sand as this may cause digestive problems or mouth and eye irritations. Climbing branches should be provided and set up to give access to a basking spot near a sunlamp. Take care not allow the iguana to touch the spotlamp as this would result in a severe burn to the animal.
Water: Can be made available to captive iguanas in a variety of ways. A standing water source, such as a filled ceramic dish, can be available for bathing and drinking. Spraying water on artificial plants and allowing the iguana to lap up this moisture is another suitable strategy. The bathtub is a wonderful and practical recreational area for a pet iguana. Swimming is great fun to observe and provides excellent exercise for the iguana. The tub is also a practical, relatively escape-proof "holding area" for the iguana while its enclosure is being cleaned. The tub should be filled so that its shallowest portion allows for submersion of about 2/3 of the iguana's body. The water should be warm and of a temperature comfortable for a human bather. Iguanas may be allowed to occasionally swim in chlorinated swimming pools as long as the activity is closely supervised and the iguana is thoroughly rinsed off with fresh water afterward.
Visual Security: A hiding place into which a captive iguana can retreat and be free from constant visual scrutiny should be provided. Visual security can be provided by supplying cardboard rolls (from toilet paper or paper towels) for small iguanas or cardboard boxes for large iguanas. Optimal visual security can be provided, however, by strategic placement of artificial plants. Because iguanas like to climb and bask, some of the branches and artificial plants provided should be arranged to allow this activity above the floor of the enclosure. Silk artificial plants are visually pleasing and easy to clean and maintain, and also withstand the use of disinfectants.
Lighting: The use of a spot lamp will also provide the day time temperature of 87 to 95 required by iguanas to properly digest food. The lamp should be off at night. A drop in temperature to 65 will not cause harm to the iguana. Additional lighting to be considered for the optimum health and growth of an iguana comes in he form of a fluorescent fixture with an ultraviolet light. Most commonly used is the Vita-lite. Ultraviolet radiation is required for the synthesis of vitamin D3 which is essential for the absorption of calcium. It can also have an effect on behavior and overall vigor. Iguanas require a light cycle of 12-14 hours per day. This can best be achieved by providing the iguana with a commercial 50 watt basking bulb placed 6 inches from the top of the enclosure and mounted in a standard clamp type light fixture from any hardware store. To provide the proper light cycle is very simple with the purchase of an electric timer that the light may be plugged into and set to rotate on and off every 12-14. Caution should always be used when placing an iguana outside to be sure and protect the iguana from predators and from over heating. NEVER PLACE AN IGUANA OUTSIDE IN DIRECT SUNLIGHT WITHIN A GLASS AQUARIUM because this has the same effect as a magnifying glass in the sun and can quickly turn an aquarium into an oven. Always provide some shade for the iguana to help prevent overheating.
Temperature: All reptiles require a warm environmental temperature to raise their body temperature and increase their metabolic rate and activity level. Iguanas are ectothermic (regulate their body temperature using an external source of heat) and bask in the sun to thermoregulate. The optimal environmental temperature is between 85 and 103 degrees F. Wild reptiles bask in direct sunlight. Temperature is very important in the digestive process of the green iguana because the symbiotic micro-organism that is responsible for aiding in the iguana's hind-gut digestion functions best if the temperature is within the POTZ. Maintaining the proper temperature also plays a key role in treating illnesses in captive iguanas. Since iguanas are ectothermic their immune system is temperature dependent and if you are treating an iguana for an illness or injury maintaining a proper POTZ is vital to the success of that treatment.
Humidity: Is essential to the general health of the iguana because these reptiles receive the majority of their water intake directly from the moisture in the air. As a result a healthy iguana will never drink from a water bowl as long as the humidity level is maintained so as a result a water bowl should only be provided as a source of humidity and a place for soaking. If an iguana begins to drink from standing water it is a good indicator that the humidity level within the enclosure is too low and that the iguana is becoming dehydrated. Humidity should be maintained at 95%-100%. For this reason it would be wise to purchase an inexpensive humidity indicator. Placing plants inside the enclosure can help to increase the humidity within it, but care should be taken to be sure that the types of plants that are used are not toxic to iguanas since iguanas will eat just about anything green. Hibiscus is a safe plant and is also a very good food source. A humidifier, can be used outside the enclosure to increase humidity. Humidifiers should never be placed within the enclosure to avoid the risk of burns.