Giant Day Gecko — Fact Sheet

Phelsuma grandis · Giant Day Gecko

Full care guide and sources

📋 At a glance

🏠 Enclosure

• Adult enclosure: 60 × 60 × 120 cm (length × width × height).
• A practical plan for one adult; furnishing and the animal’s actual size determine whether more space is needed.
• Substrate planning depth: 10 cm
• Housing: One animal per enclosure

🪨 Substrate and furnishings

The enclosure should emphasize height, secure climbing routes, and foliage.

Useful elements include:

• Bamboo tubes
• Cork backgrounds
• Live plants
• Broad leaves for drinking
• Secure elevated resting spots

💡 Lighting

• Ferguson Zone 3; aim for UVI 3-4 at the animal’s back height on the basking site. See the full care guide for the evidence and any uncertainty.
• Measure with a Solarmeter 6.5; provide a gradient to fully shaded retreats near zero UVI. Lamp percentage alone does not specify exposure.
• Photoperiod: 10-12 h; no bright night light.

🌡️ Temperature

• Basking surface: 29-32 °C

• Daytime air: 25-28 °C

• Cool-side air: 25-28 °C

• Night air: 23-25 °C

• Measure the basking surface with an infrared thermometer and air at the animal’s resting height with digital probes. A surface target is not an air temperature or a thermostat setting. Keep heat sources guarded and controlled, and provide a cooler shaded retreat.

• The daytime air range is measured away from the heated branch and includes the shaded retreat. Do not heat all branches to the basking temperature; overheating and dehydration are serious risks.

💧 Humidity and water

Phelsuma grandis needs regular hydration and usually drinks droplets from leaves and decor.

Practical goals:

• Moderate humidity by day
• Higher humidity after misting
• Good drying between wetter periods
• Fresh water available as backup

Constant stagnant wetness is not desirable. Airflow matters.

🪳 Feeding

This species is insectivorous with regular use of fruit-based prepared diets.

Suitable foods include:

• Crickets
• Roaches
• Small locusts where available
• Prepared day-gecko or fruit-gecko diets

Insects should be gut-loaded, and calcium plus vitamin support should match the lighting system.

Use a nutritionally complete gecko diet rather than plain fruit or honey, and offer only a small portion that can be removed before fermentation or mold. Adults usually stay in better condition when insects and prepared diet are portioned rather than left continuously available. Dust insects lightly with plain calcium when effective UVB is provided; use vitamin D3 and multivitamins only according to the chosen product and the rest of the diet, avoiding overlapping fortified products.

🩺 Health — warning signs

Common problems include dehydration, poor shedding, weak UVB, calcium imbalance, nose rubbing, and injuries from rough handling.

Warning signs include:

• Sunken eyes
• Stuck shed
• Weak grip
• Jaw or limb problems
• Reduced appetite
• Persistent dark stress coloration

If problems appear, first check UVB strength, lighting intensity, temperatures, hydration routine, and supplement use. Serious weakness or signs of metabolic bone disease need a reptile veterinarian.