Mourning geckos are arboreal, which means that they need more vertical space than horizontal. A colony of 2-6 adult geckos does well in a 12”x12”x18” (30x30x45 cm), which is about the equivalent of a 10-gallon tank turned on its side.
Any more than 6, and your geckos will start to pick on each other more often as they vie for personal space, which can result in severe injuries (more on that in the Handling & Body Language section). If you want a larger colony, add about 5 gallons of space per extra 2-3 geckos (or about 10 gallons per 6 geckos).
For best functionality and ease of use, I recommend investing in a front-opening style of mourning gecko vivarium. Exo Terra and Zilla both offer excellent models.
Adult mourning geckos are small enough; hatchling mourning geckos are incredibly tiny! And with small size comes a talent for mischief — specifically, escape through spaces like ventilation holes and wire ports (I’m looking at you, Exo Terra).
Some mourning gecko keepers choose to keep hatchlings in the same enclosure as the adults, which can work as long as there’s plenty of hiding spaces. However, adults are known to eat their young (!), which is why most keepers opt to remove the hatchlings and give them their own space to grow up.
Typical grow-out containers like Kritter Keepers are inappropriate as mourning gecko vivariums, but 32oz deli cups with holes poked in the top work great as a temporary habitat for 2 juveniles each.
Wait…mourning geckos can be housed together?
Yes! Mourning geckos are a rare exception of the reptile world where they do better when housed with other members of their species. In fact, housing them alone is bad for their mental health and can lead to a deterioration in physical health. They won’t be best buddies all the time (dominance squabbles will still happen), but as long as they have their own space, serious injuries are rare.
Can mourning geckos be housed with dart frogs?
Cohabitation is usually a huge taboo in reptile keeping, especially the practice of keeping different species in the same enclosure. That being said, it seems that once again mourning geckos break the rules. (Let’s be honest, mourning geckos break all the rules.)
Many dart frog keepers house mourning geckos and dart frogs together without conflict, and there are many personal accounts of success with this combination. The geckos take arboreal space that the frogs might not otherwise take, and they share similar temperature and humidity needs.
Of course, precautions should still be taken. Provide lots of space (especially vertical) to accommodate each species, and give them opportunities to avoid each other if they wish. Sticking to more terrestrial species of dart frogs can help as well.
Dart frogs are an exception! Housing mourning geckos with other species of frogs/amphibians/reptiles in general is still not advisable. Mourning geckos are frequently used as feeders for other lizards and lizard-eating snakes for a reason.