This depends but for safety and optimal health, it is recommended to keep one gecko being housed alone. Cohabitation can be stressful and can lead to issues with food, illness, and fighting among the group. One gecko will require a tank of at least 20 gallons. If you decide to keep geckos together, you should ensure that you only have one male as housing multiple will likely result in them fighting over territory. A 40-gallon tank+ is considered the minimum for 2 geckos+ more geckos being housed together.