Male iguanas become territorial as they sexually mature. Adult males will fight, don't cage together. Enclosure should provide the animal with plenty of room to climb, bask, and encourage activity. Babies do better when kept in pairs or groups, this encourages feeding and stimulation. Variety is the key to a complete nutrient rich diet.
Constant water is essential.
It is important to keep the diet varied with nutritional foods. Powdered reptile vitamins should be used with the above diet. Up to 6', but a true 5' male is rare and impressive, females up to 5'. If properly maintained may reach sexual maturity within the first 2 years. Easy, keeper must focus on the animal's basic needs which are a correct caging environment and a complete diet.