If you have a juvenile iguana, his housing can be as simple as a 55-gallon aquarium with a screen or grate top. However, once an iguana is about 12 months old and has grown into a sizeable adult (he may be 2 feet long by now), he will require a new setup. In the wild, adult iguanas live in trees, so they will need a tank with some height that can hold at least one taller branch.
A screened enclosure is a great choice for an adult iguana. You will find several different commercial options, available at some pet stores and online. As far as how big it should be, there really is no such thing as too space, and keep in mind that iguanas continue to grow throughout most of their lives, albeit at a very slow rate. An 6 ft x 5 ft x 2.5 ft enclosure will be suitable for quite a few years, but an adult iguana will require something larger. These largest of enclosures are difficult to find for sale, but can be built without too much difficulty.
No matter what kind of enclosure you buy or build, and whether you place it inside or out, he floor of your green iguana’s cage should be covered with a substrate. This can be made out of newspaper, paper bags, or other similar materials. There are also reptile cage carpets available at pet stores. The enclosure must be big enough for the iguana to be able to climb, turn around comfortably, sleep, and eat. It should contain climbing areas, basking areas, soaking or swimming areas, feeding areas, and appropriate heating and lighting.
Iguanas feel most comfortable when they are high up, able to observe from above. When providing places to climb and perch, be creative. You can use branches, carpet squares, ropes, rubber, or a variety of other materials. Any branches should be at least as wide as the iguana’s body at its widest point, and you can cut grooves into the branches or wrap them with natural rope to give your pet something to hold onto when he’s climbing.
Green iguanas are cold-blooded reptiles and require heat from their surroundings to function properly. In the wild, iguanas soak up heat from the sun and their tropical surroundings, but in captivity, this heat will need to be manufactured. The cage should be kept around 86° to 90°F for at least 10 hours a day. Providing a basking spot at one end of the enclosure will allow your iguana to stay very warm or to get gradually cooler by moving away from the basking spot.