Giant Day Gecko care: complete beginner's guide (Phelsuma grandis)
The giant day gecko (Phelsuma grandis) is one of the most spectacular reptiles you can keep. Bright green with red spots, up to 30 cm long, and very active during the day — a living work of art in your terrarium. They need UV-B and thrive in high humidity. Not a pet to cuddle, but a fascinating species for the motivated keeper.
What is a Phelsuma grandis?
The Phelsuma grandis originates from northern Madagascar. It is the largest species within the genus Phelsuma and one of the most commonly kept day geckos worldwide. They grow to 25–30 cm long and can live for 10–15 years with good care.
Characteristics:
- Bright green base color with red/orange spots on the back
- Diurnal — very active during the day
- Arboreal — live in trees and bamboo
- Not suitable for handling — observation animal
Suitable for: motivated beginners and experienced keepers
Not suitable for: people who want to handle their pet
The terrarium — size and setup
Minimum dimensions
| Age | Minimum terrarium size |
|---|---|
| Juvenile (0–6 months) | 40x40x60 cm |
| Sub-adult (6–12 months) | 50x50x80 cm |
| Adult (1 year+) | 60x60x90 cm (final size, tall model) |
Important: Phelsuma grandis is arboreal — height is essential. Always choose a vertical terrarium with good ventilation.
Setup
Phelsuma grandis needs vertical structures for climbing, basking, and hunting. Set up the terrarium like a tropical forest with bamboo or cork branches (minimum diameter 3–5 cm), hiding spots at various heights, and a cork or coconut background for grip.
| Product | Application |
|---|---|
| Repto Plant Hanging Hedra 65 cm | Hanging cover along the back wall |
| Repto Plant Vines Red & Green Fern 60 cm | Climbing plants for vertical walls |
| Repto Plant in Deco Begonia | Tropical ground cover |
| Repto Plant Hanging Green/White 46 cm | Additional cover at medium height |
Temperature and lighting
| Zone | Daytime temperature | Nighttime |
|---|---|---|
| Basking spot | 38–42°C | — |
| Warm side (ambient) | 28–30°C | 20–22°C |
| Cool side | 24–26°C | 18–20°C |
Note: Phelsuma grandis needs a higher basking temperature than smaller Phelsuma species. A true hot spot of 38–42°C is essential.
Phelsuma grandis needs UV-B for vitamin D3 production. Use a lamp with a minimum of 6–8% UV-B output (e.g., Arcadia 6% or Exo Terra Tropical). Replace the lamp every 6–12 months. Photoperiod: 13–14 hours of light in summer, 11–12 hours in winter.
The Repto Light Stand Adhesive provides stable lamp attachment without drilling.
Humidity
| Period | Humidity |
|---|---|
| Daytime (driest point) | 60–70% |
| Nighttime (after misting) | 80–90% |
Use the Repto Rainmaker 8500 for automatic misting or the Repto Druksproeier 1L for manual humidification. Day geckos lick water droplets from the walls — misting is also their source of hydration.
Nutrition — insects and fruit
| Food type | Frequency |
|---|---|
| Insects (crickets, dubia, superworms) | 4–5x per week |
| Fruit (mango, papaya, fig, banana) or nectar substitute | 3–4x per week |
| Calcium without D3 | With every insect feeding |
| Calcium with D3 | 2x per week |
| Multivitamin | 1x per week |
Use the Repto Fruit Snack Holder to hygienically offer fruit and nectar substitutes at height.
Behavior & social interaction
Phelsuma grandis is an observation animal — not suitable for handling. Males are strictly territorial — never keep two males together. A male-female pair is possible, but the female needs an egg-laying site. They communicate through color change, gular sac display, and head-bobbing.
Shedding
Phelsuma grandis sheds regularly and eats its skin — this is normal behavior. Ensure sufficient humidity. After shedding, check toes, tail tip, and eyelids for retained skin.
Maintenance & hygiene
- Daily: humidify, check water droplets on walls, check food
- Weekly: remove feces, clean glass walls
- Monthly: complete cleaning of decoration and substrate
Use the Repto Glass Cleaner for glass walls — no chemical residues, safe for your pet.
Common mistakes
Handling. Stress leads to loss of color, refusal to eat, and health problems.
No or incorrect UV-B lamp. Essential — always use a tropical UV-B lamp with 6–8% output.
Too low basking temperature. Phelsuma grandis needs a real hot spot of 38–42°C.
Two males together. Always leads to aggression and injuries.
Too dry terrarium. Humidity below 60% leads to dehydration and incomplete shedding.
✅ Phelsuma grandis setup checklist
- Vertical terrarium at least 60x60x90 cm (adult)
- UV-B lamp (6–8% output, tropical) + timer (13–14 hours)
- Basking lamp (38–42°C spot) + thermostat
- Thermometer (warm and cool side)
- Hygrometer (target: 60–90%)
- Substrate (coconut fiber or bioactive substrate)
- Vertical bamboo or cork branches (Ø 3–5 cm)
- Hiding spots at various heights
- Cork or coconut background
- Artificial plants for cover (Repto Plant line)
- Repto Rainmaker 8500 or Druksproeier 1L
- Repto Fruit Snack Holder
- Calcium without D3 + with D3 + multivitamin
- Repto Glass Cleaner
- Veterinarian who treats reptiles
Ready to start?
Phelsuma grandis is one of the most impressive reptiles you can keep — a living work of art that surprises you daily. Check out our Repto assortment for artificial plants, misting systems, and care products.
Next in this series: "Which UV lamp do you really need? Comparison per species"
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