A baby or juvenile iguana does not need a huge enclosure. In fact, a large aquarium makes a fine habitat for small iguanas. Be aware, however, that iguanas grow very quickly, and they will outgrow a large aquarium by the end of their first year. So, it is important that you plan ahead and have a large enclosure ready. Inadequately warm temperatures prevent iguanas from properly digesting their food and absorbing nutrients.
Growth is stunted and malnutrition results.
In addition, an iguana that is kept too cool will be uncomfortable and inactive. Within the habitat, a range of temperatures should be provided so that your iguana can regulate its body temperature by moving back and forth between cooler and warmer areas. This means that you must provide heat at night without the use of lights. Many methods are available for doing so, and are discussed further in the Heating, Lighting and Humidity section. UVA stimulates natural behaviors by providing a component of natural sunlight.