A 20 gallon enclosure is a good size for an adult crested gecko. A taller enclosure is preferred over a long enclosure. The Exo-Terra terrarium measuring 18x18x24 is one of the best to house an adult crested gecko in. Vines, plants, and logs should be placed for climbing and hiding. A lid must be kept on at all times as crested geckos can easily climb up glass and jump out. Females can be housed together. Males must be housed singly.