A starting group of mourning geckos needs at least a 12 by 12 by 18 inch tall enclosure, but the honest recommendation is 18 by 18 by 24 inches, because this species does not stay a starting group for long. Mourning geckos are three to four inches of pale, big-eyed climber, and nearly every one is female, producing fertile eggs without a mate. Two geckos become six, then a dozen, and an enclosure chosen only for the founders becomes crowded while the keeper is still admiring the eggs glued in its corners.
Space for the Colony You Will Have
Plan the adult colony's territory first and let the current residents grow into it. A taller enclosure with layered planting gives subordinate geckos escape routes and separate sleeping spots, which matters because even these social little geckos squabble over favourite hides and feeding ledges. Provide far more small retreats than geckos: bamboo sections, cork tubes, and curled leaves at several heights, so a chased gecko always has somewhere unoccupied to land. Spread two or three feeding stations through the foliage instead of one ledge every gecko must contest.
Eggs Glued Where They Fall
Mourning geckos glue their paired eggs to surfaces, often inside bamboo or behind bark, and the eggs generally cannot be moved without damage, so babies hatch inside the main enclosure. That makes escape-proofing part of the space decision: hatchlings are tiny enough to slip through standard ventilation gaps and door seams, and an enclosure meant for a colony needs fine mesh and gap checks done before the first eggs appear. Decide honestly where future youngsters will go, since rehoming a steady stream of geckos is part of keeping this species, not an unexpected emergency.
Small Geckos, Shared Duties
Daily care in a colony enclosure is about distribution rather than volume: misting that reaches the whole height, food stations refreshed where the shyest geckos actually feed, and dead leaves and waste removed without dismantling everyone's hides. A front-opening enclosure at the larger size makes that upkeep calmer, since you can work in one corner while the colony retreats to another. Keep handling minimal, as these geckos are quick, delicate, and shed their skin readily when grabbed, and observe feeding at dusk when the whole group emerges. Note the feeding stations by position in your care notes rather than trusting memory, because in a dense colony tank it is easy to refresh the obvious front ledge twice and miss the hidden one at the back where the youngest, shyest geckos wait their turn.
When the Terrarium Is Full
Signs of genuine crowding include geckos sleeping exposed on the glass for lack of a hide, repeated dropped tails from squabbles, thin youngsters that never reach the food stations, and eggs appearing in ever more exposed places. At that point the answers are a larger enclosure, a second one, or rehoming juveniles, not tighter planting in the same box. Once the colony's home is sized and planted, KinsLe's Family Sharing keeps the geckos' profile, feeding routine, and population notes shared across the household, so everyone knows the current headcount and who fed last.