Giant Day Gecko (Phelsuma grandis)
Giant day geckos (Phelsuma grandis) are a diurnal, omnivorous type of arboreal gecko primarily native to northern and eastern Madagascar, although they are invasive in many other places around the world. They prefer tropical forest for habitat, and as a strictly arboreal species, they spend most of their lives up off the ground.
Giant day geckos generally grow 9-11″ / 23-28cm long, with females being smaller than males. They can be identified by their bright green color, with a bold red stripe from the nostril to the eye on each side. Some individuals may have additional red, orange, and/or blue markings depending on locality and lineage. Their bodies have a sharply tapered snout, round lidless eyes, sticky toe pads, a moderate-length tail, and delicate velvety skin.
Giant day geckos are among the most popular day geckos in the hobby due to their size and relative hardiness. If you pay attention to providing high-quality giant day gecko care, you may expect your pet to enjoy a lifespan of 15-20 years.
Giant Day Gecko Shopping List
These are products I personally recommend for setting up a functional giant day gecko terrarium. Some of the links in this care sheet are paid links — if you’d like to know why ReptiFiles uses paid links, visit this page.
- Front-opening 24”L x 24”W x 48”H terrarium, or larger
- 40w Exo Terra Daytime Heat Lamp, x2
- 18″ Zoo Med Naturalistic Hood
- 22″ Zoo Med T5 HO Reptisun 5.0 OR Arcadia Forest 6% UVB bulb
- 24″ Arcadia ProT5 OR Vivarium Electronics T5 HO fixture
- 22″ Arcadia Jungle Dawn LED Bar
- Zilla 24/7 Digital Power Center
- Zoo Med Digital Thermometer/Hygrometer Combo, x2
- Exo Terra Mister
- Zoo Med Eco Earth, 20+ quarts
- Environmental enrichment
- Magnetic Gecko Ledge, small
- Pangea Biodegradable Gecko Feeding Cups, small
- Crested gecko meal replacement powder
- Miner-All Outdoor calcium powder
Giant Day Gecko Enclosure Size
Giant day geckos need an enclosure that is large enough to give them adequate opportunity to explore, hunt, and generally exercise natural behaviors. They are also arboreal, which means that they need a terrarium that provides a generous amount of climbing space. Considering that giant day geckos can grow up to 11″/28cm long (and sometimes larger), the minimum recommended enclosure size for a single giant day gecko is 24”L x 24”W x 48”H / 60 x 60 x 120 cm or similar. Where possible, larger is always better!
Here are some enclosures that are appropriate for housing giant day geckos:
- Zen Habitats 2’x2’x4′ PVC Panel Reptile Enclosure
- Maximum Reptile Essential 4 Vertical PVC & Aluminum Enclosure 2.0
Can multiple giant day geckos be housed in the same enclosure?
Day geckos have been historically housed together successfully in breeding pairs or small breeding groups of one male and multiple females. However, if you don’t intend to breed day geckos, then it’s best practice to keep only one or a group of strictly females.
To house multiple day geckos together, the size of the enclosure needs to be proportionately increased so the geckos can get away from each other as needed.
Lighting & UVB for Giant Day Geckos
Giant day geckos are diurnal, which means that they are primarily active during the day. This means that they need access to a basking area, are exposed to direct UVB during the day, and have relatively poor night vision. Lights should be on for 13 hours/day during summer and 11 hours/day during winter with incremental adjustments in-between.
Giant day geckos require UVB lighting as part of their setup in order to survive and produce their best color. UVB lighting can be tricky, because in order to get the right strength of UVB (measured by UV Index, or UVI), distance must be considered.
As a rough estimate, to provide appropriate UVB to a giant day gecko, you will need one of the following lamps, depending on the enclosure’s height. Measurements assume that the lamp is being mounted over a mesh top, measured from the gecko to the lamp.
- Arcadia ShadeDweller Arboreal kit — 4-6″ / 10-15cm
- Arcadia Forest 6% — 7-9″ / 17-23cm
- Zoo Med T5 HO Reptisun 5.0 — 7-9″ / 17-23cm
For best results, use a highly reflective, reptile-specific fixture (ex: Vivarium Electronics, Arcadia ProT5), not hardware store fixtures. UVB bulbs must be replaced every 12 months in order to remain effective.
(These recommendations are approximations. It is strongly recommended to use a Solarmeter 6.5 to determine the best placement to achieve a UVI of 3.0-4.0 in the basking area at the top of the enclosure.)
As a diurnal species, it’s also best practice to provide bright light with a color temperature of around 6500K in addition to UVB and heat lamps. Giant day geckos with access to bright lighting are likely to be more active, have better appetites, and display better color.
Giant Day Gecko Temperature Requirements
Humans are warm-blooded, which means that our body temperature is automatically regulated. Giant day geckos, however, are cold-blooded, and they need to move between areas of different temperatures in order to regulate their body temperature. In the wild, giant geckos warm up by basking in a warm patch of sunlight. In captivity, sunlight can be replicated with a white incandescent heat lamp.
- Basking area temperature: 85-90°F (29-32°C)
- Cool zone temperature: 77-82°F (25-28°C)
- Nighttime temperature: 73-77°F (23-25°C)
Due to their size, you will need two ~40w incandescent bulbs for basking, such as the the Exo Terra Daytime Heat Lamp in a ceramic socket hood. This wattage should be plenty, but results will vary based on your room temperature. If you notice that the basking area is too warm, dial down the heat down with a lamp dimmer or switch to a lower wattage bulb. If your basking area is too cool, you will need a higher wattage bulb.
The basking area should be a vine or branch directly under the heat lamp. Because your gecko is arboreal and will be living in a tall enclosure, the warmest temperatures will be at the top (near the heat lamp), and the coolest temperatures will be toward the bottom. You will need vines, branches, and foliage at all levels to allow for proper thermoregulation.
To track basking temperature, use a digital probe thermometer, with the probe zip-tied to the basking surface under the heat source. Most reptile-brand digital probe thermometers function well.
Giant Day Gecko Humidity Requirements
Giant day geckos do best in a moderate- to high-humidity environment, with an average humidity between 40-75% as measured by a digital probe hygrometer with the probe placed in the middle of the enclosure. Humidity levels that are consistently too high or low can cause health problems for your gecko. However, it is natural for humidity to be lower in the warm area and higher in the cool area. It is also normal and healthy for humidity levels to rise at night and fall during the day.
To raise the humidity in your gecko’s enclosure (and provide an extra source of drinking water), use a pump-style pressure sprayer such as the Exo Terra Mister to wet down the enclosure every morning and evening.
Giant Day Gecko Substrate Options
Because giant day geckos are arboreal (tree-dwelling), they don’t spend much time on the ground. Although it’s not necessary to use bedding for them, it’s very useful for helping to stabilize humidity. It also acts as a cushion if they fall from their perch, which may happen while they are hunting.
It’s best to use a moisture-retentive substrate that is similar to the soil in a giant day gecko’s natural habitat. Here are some reliable options:
- DIY tropical mix: 60% organic topsoil, 40% coconut fiber
- Zoo Med Reptisoil
- Zoo Med Eco Earth
- Exo Terra Plantation Soil
- The Bio Dude Terra Fauna bioactive kit
Only 2″ / 10cm should be needed, unless you are planting the plants directly into the substrate. For best results, add a generous layer of leaf litter on top.
Feces and urates should be removed daily, and contaminated substrate should be scooped out and replaced. Substrate should be completely replaced once every 3-4 months, depending on your needs.
Decorating Your Giant Day Gecko Terrarium
Decorations play a vital role in your gecko’s enclosure as environmental enrichment. Enrichment items encourage exercise, stimulate your pet’s natural instincts, and help promote overall wellbeing. And, of course, they make the enclosure look nicer! Without décor, your terrarium is just a glass box with dirt and a feeding ledge. Just because day geckos can climb up glass doesn’t mean they shouldn’t have other climbing materials available. They also need places to hide that are not on the ground.
Here are some ideas to get you started:
- cork hollows
- live plants (ex: dracaena, sanseveria, pothos, philodendron, bromelia)
- magnetic ledges
Arrange these items in a way that encourages your gecko to climb and explore, and provides areas of both light and shade. Artificial plants are best avoided with day geckos.
Feeding Your Giant Day Gecko
Giant day geckos are omnivores, which means that they need a balanced diet of both plant- and animal-based foods to get the nutrition that they need. In the wild, they eat mostly insects, flower nectar, and fruit juice. As pets, this diet can be re-created with a balance of meal replacement powder and live insects.
How often giant day geckos need to eat depends on age:
- Juveniles (0-6 months) — insects daily, CGD every other day
- Subadults and Adults (>6 months) — insects 2-3x/week, CGD 1x/week
Crested gecko diet (CGD) must be offered via a wall-mounted feeding ledge, not placed on the ground. Personally I prefer magnetic mounts to suction cups.
Best feeder insects for giant day geckos: crickets, dubia roaches, discoid roaches, red runner roaches, red head roaches, grasshoppers/locusts, hornworms, silkworms
The key to providing a healthy, balanced diet for your pet is VARIETY. Provide as varied of a diet as you possibly can, and you will be rewarded with a healthier pet that always looks forward to mealtime. I prefer to use a rotation of at least 3 different kinds/flavors of CGD.
Crested gecko diet is already fortified and balanced with a variety of vitamins and minerals. However, feeder insects need to be “dusted” with a light coating of calcium powder before every feeding to balance the calcium-phosphorus ratio.
Although your gecko will get drinking water from daily mistings, it’s best to always keep a bowl of clean water available on the feeding ledge. This bowl should be scrubbed out with veterinary disinfectant such as Rescue or F10SC weekly for good hygiene.
Handling Your Giant Day Gecko
Giant day geckos are large enough to be handled safely, but it’s important to remember that they still have extremely delicate skin like other day geckos. If you want to try interacting with your gecko, I recommend limiting interactions to offering insect prey by hand/soft-tipped feeding tongs or putting a dab of CGD on your finger for them to lick. If your gecko learns to trust you enough, it may walk onto your hand/arm. However, never grab it!
Wait at least 2 weeks for the gecko to settle into its new home before trying to introduce yourself.
Baines, F. M., Chattell, J., Dale, J., Garrick, D., Gill, I., Goetz, M., Skelton, T., & Swatman, M. (2016). How much UVB does my reptile need? The UV-Tool, a guide to the selection of UV lighting for reptiles and amphibians in captivity. Journal of Zoo and Aquarium Research, 1, 56. https://doi.org/10.19227/jzar.v4i1.150
Madagascar Giant Day Gecko (Phelsuma grandis). (n.d.). INaturalist. Retrieved December 28, 2021, from https://www.inaturalist.org/taxa/34041-Phelsuma-grandis
General Care. (2017). Phelsuma Farm. https://www.daygeckos.co.uk/general-care/
McKeown, S. (1993). The General Care and Maintenance of Day Geckos. Advanced Vivarium Systems.
Medium UV Species. (n.d.). Arcadia Reptile. Retrieved December 27, 2021, from https://www.arcadiareptile.com/lighting/medium-uv-species/
Rundquist, E. M. (1995). Day Geckos. T.F.H. Publications.
The ReptiFiles Giant Day Gecko Care Sheet is a simplified care summary, not a full ReptiFiles care guide. While I have done my best to ensure that the information contained is accurate, due to time constraints, the research behind ReptiFiles care sheets is not as thorough as the research involved with my full-length care guides. I strongly encourage readers to do their own research from high-quality, reputable sources outside of just this care sheet as part of preparing for your new pet reptile.