New Caledonian Giant Gecko Care Sheet

The New Caledonian giant gecko is Rhacodactylus leachianus, commonly known worldwide as the “Leachianus.” It is one of the largest gecko species, and husbandry can be relatively stable once the environment is set up correctly. However, no setup is completely stress-free. This care sheet is shared so Terranima readers can keep this species with more confidence and consistency. There is no single absolute “correct” method. Details can vary by keeper preference and circumstances. Still, any setup that causes avoidable stress should be minimized. This guide focuses on broadly recommended, practical standards.

Habitat Leachianus is broadly divided into two locality groups: GT (Grand Terre) and Island. Each group can be subdivided further, but this care sheet starts with core fundamentals. GT locality animals commonly reach around 250–400 g, while Island locality animals commonly reach around 150–250 g.

Enclosure The key objective is to create a setup where the animal feels secure. The two most important foundation elements are hiding structure and substrate. Some keepers use paper towels or pads, but we generally recommend a mix of Coconut Husk Chips and Coconut Peat. Leachianus has strong claws, and smooth paper surfaces can catch claws and restrict natural movement. Coconut-based substrates also develop beneficial micro-life over time, becoming a more bioactive, stable base while retaining moisture well. This makes humidity control easier. For hides, cork tubes are highly practical. In the wild, this species uses trees and tree hollows, so provide tubes wide enough for stress-free entry and exit.

If you introduce isopods into the enclosure substrate, they can help break down waste and reduce maintenance load. But some individuals may show feeding responses toward isopods. So the substrate should be deep enough for isopods to burrow, at least 3 cm, preferably deeper.

Porcellio laevis “Dairy Cow” isopods attached to a cork tube

Note on GI impaction: Some keepers worry about intestinal blockage when using coconut substrates. This can happen if substrate enters the feeding dish and is swallowed with food. If this is a concern, place a plastic mesh layer over the substrate and set the feeding dish on top. This reduces substrate contamination in the dish and lowers accidental ingestion risk.

On Whether to Provide Hides Some people believe Leachianus becomes “calmer” without hides. In practice, this often means the animal is chronically insecure and behaviorally suppressed. It may look calm, but it is frequently just shut down. Wild Leachianus naturally retreats into tree hollows. When a hide is recognized as territory, defensive reactions around that area can occur. As many animals mature (around 2–3 years), fear responses often decrease and behavior becomes steadier. Both males and females can also show seasonal shifts in aggression around breeding and laying periods, which is a normal biological response.

A pair of Leachianus resting inside a hide

Enclosure size: 38 × 40 × 45 cm

Enclosure size: 90 × 45 × 45 cm

Enclosure Size This topic has many differing opinions among breeders. There is no single universal answer, so it is better to understand practical do’s and don’ts rather than chase one fixed rule.

The size chart above is a practical guideline. We generally recommend relatively spacious enclosures. In very small setups, feeding response may look strong because food is close, but activity often drops and obesity risk increases. Obesity can affect hormonal balance, sexual maturity, laying quality, and breeding consistency. Because Leachianus is nocturnal, daytime activity may appear low, but with enough space, nighttime movement is usually much better. We also generally avoid very tall setups beyond about 60 cm. Large adults may approach 400 g, and on smooth glass, the adhesive toe pads may not hold body mass reliably, increasing fall risk. Repeated falls in very tall enclosures (especially around 90 cm+) can cause injury, and can also condition fear that reduces normal movement.

New Caledonia climate chart (reference)

Temperature and Humidity Common target ranges are 23–28°C and around 60% humidity. (Example misting rhythm: once daily on humid days, twice daily on dry days, lightly misting to keep the enclosure gently moist.) You do not need to perfectly reproduce New Caledonia’s exact day–night fluctuation for routine maintenance and growth. For many keepers, stable “comfortable room” conditions are workable and easier to manage. Avoid direct airflow from heating/cooling devices onto the animal. Sudden drafts can contribute to dehydration and thermal stress. Leachianus is ectothermic and not resistant to abrupt temperature shifts. Low temperatures can reduce activity and feeding; high temperatures can impair metabolism and increase dehydration risk. Some individuals can adapt if temperatures are raised gradually toward ~30°C, and in some cases growth may accelerate. People sometimes say they can “survive” around 16°C, but survival and long-term comfort are not the same thing.

Superfood (complete diet) example (Leapin Leachies superfood reference photo)

Superfood + fruit

Feeding As Leachianus keeping expanded globally, many powdered “superfood” diets became available. A common working mix is roughly 1 part powder to 2 parts water. Feeding interval can be every 2 days or every 3 days, adjusted to individual response and keeper routine. There is no single fixed portion rule. Observe consumption and tune amounts in practice. If the dish is consistently emptied for multiple feedings, move up to a slightly larger dish. Because geckos usually approach food in a low posture, a properly filled dish often improves first feeding response. Additional nutrition (fruit/live prey) Modern superfoods can support husbandry alone, but they are not identical to wild dietary diversity. Some keepers still supplement for broader nutrient coverage. Fruit options include banana, blueberry, watermelon, strawberry, etc. Banana is often the easiest practical choice for consistency and texture. Live prey options may include crickets, roaches, and small feeder mice. These can help body condition and growth, but response varies by individual, especially in animals long conditioned to prepared diets. Live prey is generally not recommended for small babies. A practical threshold is around 40 g body weight, starting with prey smaller than the gecko’s head.

1) Breeding prerequisite: sexual maturity The primary prerequisite for safe, successful breeding is maturity in both male and female. Pairing immature animals can trigger territorial conflict, bites, severe stress, anorexia, and dehydration. In males, maturity markers include development around the vent and clearer hemipenal bulge. In females, laying infertile eggs can be one maturity indicator. General age references are often ~18 months for males and ~28–36 months for females, but variation by lineage, individual growth, temperature, and nutrition is large. Large-form animals may require longer before entering breeding range. Use age as reference only, and confirm with morphology and behavior. 2) Signs that breeding season is approaching As maturity progresses, behavior may shift: heightened sensitivity, defensive reactions when opening the enclosure, reduced feeding response, night calling, and sudden digging behavior. When these signs overlap, move into cooling and pairing preparation. 3) Winter operation (cooling) In the wild, winter-to-spring thermal transition helps regulate breeding rhythm. In captivity, practical management usually favors creating seasonal contrast rather than extreme cold targets. If room temperature naturally drops in winter, that may already provide a cooling effect. In many setups, seasonal thermal difference matters more than a strict absolute minimum. Lighting-hour adjustment is sometimes used, but temperature structure is usually the stronger driver. Earlier cooling can shift ovulation/laying earlier, so plan annual scheduling accordingly.

Injuries observed during pair formation

4) Pairing/cohabitation: the most difficult and most critical phase Many Leachianus breeding failures begin with early cohabitation conflict. So before fertility, prioritize safety: avoid biting trauma, dehydration, and infection. 4-1) Body-size pairing Similar-sized pairs are usually safer. When sizes differ, a slightly larger male often improves mating success. If the female is much larger/stronger, restraint and successful copulation may drop while conflict rises. 4-2) Reset layout before introduction Rearranging cork tubes and hide positions before pairing can reduce territorial fixation and soften first-contact clashes. 4-3) Timing of introduction Starting cohabitation in cooler periods can reduce overheated conflict. Lower-metabolism periods are often easier for introduction. 4-4) “Getting along” is not equal to breeding success Long-term peaceful cohabitation can still result in infertile clutches if pair stimulus declines. Success should be judged by consistent fertile egg production, not appearance of friendliness. 4-5) Reading wounds Neck bite marks on females may be mating-associated. But deep injuries on head/body/limbs suggest aggressive incompatibility and may require separation. Jaw-lock behavior is not always immediately fatal if superficial, but heavy bleeding or deep tissue/bone exposure is an immediate stop signal. 4-6) Access to safe space If one animal is constantly displaced and cannot secure a stable retreat, anorexia, depletion, and eventual collapse can follow. Watch for extreme dominance patterns such as hide monopolization or severe vertical-space exclusion.

Dehydrated Leachianus

5) Trouble management: focus on dehydration and infection During cohabitation incidents, secondary dehydration/infection is often more dangerous than the wound itself. Animals with skin loss can dehydrate quickly and deteriorate in a short time. Dehydration signs: 1. Sunken eyes 2. Reduced body elasticity/turgor 3. Reduced activity and poor grip 4. General lethargy If dehydration is suspected, prioritize rehydration and environmental correction immediately. In severe cases, voluntary drinking may be absent; short-term humidity support with proper ventilation may help recovery. If swelling, persistent bleeding, suspected necrosis, or prolonged anorexia occurs, consult a reptile-capable veterinary clinic promptly. 6) Pairing variants: multiple-female rotation and separation risk Rotating multiple females through one male enclosure is practiced in some programs. It can broaden pairing combinations, but frequent switching may increase stress reactivity. Design based on temperament and stress tolerance. The right balance between efficiency and stability depends on keeper strategy. 7) Post-copulation timing design Days from mating to laying vary widely by individual. A key practical point: once shell formation is well underway, later mating may not result in fertilization. Operationally, introducing pairs before the likely ovulation window is usually more stable.

Leachianus laying eggs on the ground

8) Laying cycle: keep temperature and interval balanced 8-1) Typical interval About 6 weeks is a common baseline. At higher temperatures, cycles can shorten to 4–5 weeks, but excessive shortening may destabilize fertilization and shell formation, increasing infertile eggs. Steady rhythm usually supports better parental condition than aggressive heat-driven acceleration. 8-2) Eggs per clutch Two eggs is the standard pattern. Occasionally eggs are laid on separate days; in those cases, the first egg can be infertile or poor quality. Early-season clutches may be less stable, so evaluate trend across later clutches instead of over-interpreting the first one.

Poor-quality Leachianus eggs

Well-formed Leachianus eggs

9) Egg quality check: visual risk signs Healthy eggs are typically relatively smooth and firm, often described as having a porcelain-like surface. In contrast, heavily bumpy “golf-ball-like” eggs may show lower hatch consistency and weaker post-hatch stability. Shell quality reflects not only calcium but overall nutritional and physiological status. Avoid single-cause assumptions; review breeding load, body condition, feeding program, and late-season depletion together.

10) Incubation: stabilize long-duration runs with substrate, humidity, and ventilation Leachianus incubation often runs long, so stable thermal/humidity control plus appropriate ventilation is essential. Common media include moisture-retentive incubation substrates, perlite, and vermiculite. Very fine media can compact when wet and reduce airflow around the egg surface. Also note that hygrometer values are relative humidity; actual moisture context changes with temperature. Use real substrate contact moisture around eggs—not only numeric RH—as your operating reference. Avoid both over-dry and over-wet conditions. Excess moisture can promote mold/rot, so periodic ventilation is mandatory.

Leachianus estimated hatch timing by temperature

11) Temperature, hatch duration, and sex ratio: avoid extremes Leachianus is known as a species where early incubation temperature can influence sex ratio. This is not a strict 100% switch, but stable management generally improves directional consistency. Extreme low/high temperatures raise failure risk, especially later in development, so prioritize safe operating ranges. Because incubator display and true internal temperature can differ, use an independent sensor whenever possible. 12) Delayed hatch and egg cutting: intervene cautiously Egg cutting is timing-sensitive; premature intervention can expose underdeveloped hatchlings. If eggs remain stable without rot/mold signs, waiting is often safer. For poor-shell eggs, hatch-exit failure risk can increase near term, so delayed cases may require cautious case-by-case judgment. If you observe foul odor, severe discoloration, or excessive condensation, inspect conditions first and consult experienced keepers or specialists when needed. This concludes the Leachianus care sheet. We hope it provides practical support for your husbandry. Unexpected events can always occur, so if problems arise, please contact Terranima for support.