Don't mistake 18×18×24 for an adult crested gecko tank

It is easy to mistake an 18 × 18 × 24 inch terrarium for a proper adult home because many retailers still label it “adult size”. At 60 cm tall, though, it quickly becomes crowded once you add safe branches, cover, feeding ledges and the clear routes a crested gecko needs to climb, rest and feel secure.

An adult crested gecko tank size should be a tall, front-opening 45 × 45 × 90 cm (18 × 18 × 36 inch) enclosure for one gecko. The older 45 × 45 × 60 cm size is a bare minimum rather than the welfare-first target.

Choose 45 × 45 × 90 cm for an adult gecko

For one adult crested gecko, choose a 45 × 45 × 90 cm vertical enclosure as the long-term home.

A crested gecko, or Correlophus ciliatus, is arboreal. Arboreal means it spends much of its life off the ground, much like a person choosing stairs and landings rather than sitting on a bare floor. It comes from the vegetation of New Caledonia, so a tall enclosure suits its natural way of moving.

Is 18 × 18 × 36 the adult target?

Yes. An 18 × 18 × 36 inch enclosure is about 45 × 45 × 90 cm and is the sensible adult target for one crested gecko. Its extra height lets you create a low route, a middle resting level and an upper canopy without forcing everything into one crowded patch.

Can an adult live in 18 × 18 × 24?

An 18 × 18 × 24 inch enclosure can house an adult at the bare minimum, but it is not the preferred long-term size. Improve the furnishing now, then plan an upgrade rather than adding a second gecko or more clutter to compensate.

Why 45 × 45 × 60 cm is no longer the best buy

The 30 cm difference between 60 cm and 90 cm height creates useful territory, not empty air.

What does 30 cm extra height change?

Thirty extra centimetres allow at least two routes between the base and canopy, rather than one steep branch. One route can pass through foliage, and another can lead to food, so the gecko has choices instead of a single exposed path.

Litres measure total internal volume, not the shape of the home. A low, wide enclosure can hold similar litres to a taller model but offers far less climbing distance, much as a wide bungalow has more floor space but no upstairs rooms.

Use this simple calculation only to compare capacity: length × depth × height in cm, then divide by 1,000, equals litres. For example, 45 × 45 × 90 cm equals about 182 litres, while 45 × 45 × 60 cm equals about 122 litres. The extra 60 litres matter because they are mostly vertical space.

The difference between a 45 × 45 × 60 cm enclosure and a 45 × 45 × 90 cm enclosure is partly why crested gecko care advice can look inconsistent. Older care sheets and retailer labels often treat 18 × 18 × 24 inches as an adult crested gecko enclosure because it provides the traditional minimum footprint and height. A welfare-first crested gecko vivarium size recommendation, however, gives more weight to usable vertical territory, cover and separate activity levels.

Neither measurement changes the gecko’s biology; the 90 cm model simply makes it easier to create a better-furnished long-term home without compromising access to food or hiding places.

Match enclosure size to stage and feeding

Upgrade a young gecko when it eats reliably, holds or gains weight, can be found without dismantling the décor, and has enough foliage cover in the larger home.

These weights are guide ranges, not a diagnosis tool. A reptile vet should assess unexplained weight loss, poor feeding, weakness or changes in droppings. The Animal Welfare Act 2006 requires keepers in England to meet welfare needs, including a suitable environment; the legal text is available through UK legislation.

When is a larger tank too soon?

A larger enclosure is too soon when a hatchling cannot consistently find its feeding ledge within the first few nights. Keep the smaller enclosure well furnished, not bare, and use a shallow dish or ledge in the usual place so feeding can be checked.

Does weight matter more than age?

Weight and feeding behaviour matter more than age alone when choosing an upgrade. A 10 g gecko eating well and using several routes may cope better than a larger gecko that has in recent months stopped eating after a move.

Test usable climbing space, not litres

A good arboreal vivarium lets a crested gecko climb from low to high cover through connected branches, shelves and foliage, then reach food and water without a long exposed jump.

Can it climb from floor to canopy?

A gecko should have two connected routes from substrate to upper cover. One may be a cork tube and foliage route, while another can be a branch-and-ledge route. This reduces the need for risky jumps across open glass.

Can it find food after lights out?

A feeding ledge should be reachable from a branch within a short climb and should not sit under dripping spray. Crested geckos are usually active after dark, so place food in a repeatable spot and inspect it the next day.

Tank size works alongside environmental control. In a vertical terrarium, aim for roughly 22–26°C during the day, with a modest night-time drop where the room allows it; prolonged temperatures above about 28°C can be dangerous. Humidity should rise after evening misting, often to around 70–80%, then fall as the enclosure dries during the day rather than remaining constantly wet. Use a digital thermometer and hygrometer at different levels, provide gentle cross-ventilation, and give a consistent day-and-night light cycle.

Low-level UVB, where correctly installed, should be available with shaded areas. Good arboreal reptile housing is not just crested gecko climbing space: it is a layout with safe temperature, airflow and cover at every level.

Buy a UK vivarium beyond the starter kit

Choose a front-opening, escape-secure 45 × 45 × 90 cm enclosure with balanced ventilation, moisture-resistant materials and safe room for lights and cables.

Which doors, vents and lids matter?

Front-opening doors make feeding and cleaning less intrusive than lifting a lid over the enclosure. Doors should close flush, ideally with a lock or clip, because crested geckos can push through surprisingly small gaps.

Adult crested geckos should be housed one per enclosure, even in a spacious 45 × 45 × 90 cm vivarium. Cohabitation can cause hidden stress, bitten tails, food competition and unplanned breeding before the keeper notices a problem.

If you want a bioactive front-opening vivarium, check more than its external dimensions. The base should safely hold a drainage layer, mesh barrier and moisture-tolerant substrate without reducing the usable lower climbing area, while doors and seals must resist regular misting. Choose live plants that can tolerate the enclosure conditions and use cork, branches and vivarium foliage cover to make connected routes rather than a dense wall that blocks inspection.

A clean-up crew can process some waste, but it does not replace removing soiled substrate, refreshing food dishes or monitoring droppings. Bioactive compatibility is especially useful when planning a crested gecko upgrade into its permanent adult enclosure.

Questions & answers

What size tank is best for a crested gecko?

One adult crested gecko does best in a 45 × 45 × 90 cm, or 18 × 18 × 36 inch, front-opening enclosure. Furnish it with connected branches and foliage, because empty height does not create usable climbing space.

Is 12x12x18 too small for a crested gecko?

A 12 × 12 × 18 inch enclosure suits only a monitored hatchling or small juvenile, usually below about 15 g. It is not an adult enclosure, even if the gecko appears to fit inside it.

Is 18x18x24 big enough for an adult crested gecko?

An 18 × 18 × 24 inch enclosure is the bare minimum for an adult, not the preferred long-term size. Choose 18 × 18 × 36 when buying anew because the extra 12 inches allow better climbing routes and cover.

Should i keep two crested geckos in one tank?

No, keep one adult crested gecko per enclosure to avoid stress, injuries and food competition. A large vivarium does not make cohabitation reliably safe, and mixed-sex pairs can produce unplanned eggs.

Make the adult enclosure your first purchase

The clearest buying decision is simple: choose 45 × 45 × 90 cm if your gecko is adult or you are planning its lifelong home.

• Minimum Space for Adult Growth Isn't Measured in Litres
• Don't Buy an Exotic Pet Vivarium by Price Alone

The Reptile Vivarium Team

Our guides are based on comparing specialised reptile care sources, keeper community input, and recognised husbandry guidelines — we are not vets or professional breeders, and we say so where it matters.