Reptiles · Geckos
Madagascar Giant Day Gecko
Phelsuma grandis
Brilliant green, diurnal, strictly hands-offIntermediate
- Lifespan
- 10-15 years
- Size
- 25-30 cm
- Social needs
- Solitary; house singly
- Time
- Medium; daily feed, mist, lighting
- Cost
- Medium-High
- Diet
- Omnivore (insects + nectar/fruit)
Overview
What is this animal?
- The Madagascar giant day gecko is a large, vivid emerald-green, diurnal gecko from northern Madagascar, often marked with red flecks.
- Unlike most pet geckos it is active and brightly coloured in daylight, which makes it a striking display animal, but it is a look-don't-touch species with delicate, tear-prone skin.
- It is more demanding than the nocturnal beginner geckos because it genuinely needs strong UVB, a basking gradient and high humidity.
- It suits keepers who want a planted vivarium to observe rather than a gecko to handle, and rewards good husbandry with bold, interesting behaviour.
Temperament
- Day geckos are fast, alert and largely hands-off; they stress easily when handled and their delicate skin can be injured by restraint, so they are best enjoyed as an active display species.
- They are diurnal, so unlike most geckos they are at their most visible during the day.
- They are territorial and must be housed singly outside of supervised, carefully managed breeding.
- Two adults, especially males, will fight fiercely.
- A single gecko in a well-planted vivarium is the correct, welfare-friendly setup.
A good fit for
- Keepers wanting a vivid display gecko
- Hobbyists who enjoy planted bioactive vivariums
- Those happy not to handle their reptile
- People who can provide strong UVB and humidity
Common mistakes to avoid
- Handling that tears their fragile skin
- Inadequate UVB and calcium
- Housing two together (serious fights)
- Humidity too low or stagnant and mouldy
Enclosure
Minimum 2,030 cm² of floor (315 sq in) · 45 × 45 × 60 cm
Must be housed alone. Solitary; house singly
- Provide a tall, well-planted vivarium of at least 45x45x60cm for one adult, furnished with bamboo, broad-leaved live plants and cork for climbing and basking.
- As an arboreal, diurnal species it needs both vertical space and bright lighting, so a bioactive planted setup suits it well.
- Maintain a basking spot of around 30-32C with a cooler ambient of 24-26C, and provide a moderate-to-high output UVB tube, which is essential for this sun-loving lizard.
- Keep humidity around 60-80% by misting once or twice daily, allowing partial drying between mistings to prevent stagnant, mouldy conditions.
Supplies
Setup
- Enclosure
- Heating and thermostat
- Low-output UVB fixture and bulb
- Thermometers and hygrometer
- Substrate, hides including a humid hide, decor
Ongoing
- Complete powdered fruit-gecko diet (for cresteds, gargoyles, chahouas, mourning geckos)
- Live crickets, dubia roaches or black soldier fly larvae
- Plain calcium powder without D3
- Calcium with D3 plus a reptile multivitamin
- Feeder gut-load and a ventilated feeder tub
- Shallow ledge-mounted feeding cups
- Blunt-tipped feeding tongs
- Shallow water dish
Safe substrate: Topsoil and play sand mix for arid geckos · Coco fibre and orchid bark for tropical geckos · Paper towel
Care routine
Daily
- Check temperatures and humidity
- Fresh water bowl
- Look the animal over
- Mist the enclosure
- Spot-clean waste and uneaten food
Weekly
- Feed insects or prepared dietevery 2 days
- Check toes, tail tip and eyes after a shedevery 3 days
- Short handling session, species permittingevery 3 days
- Re-damp the humid hide
Monthly
- Weigh-inevery 2 weeks
- Deep-clean the enclosure
- Test thermostats, lamps and guards
Less often
- Refresh the substrateevery 3 months
- Replace the UVB lampevery 6 months
Vet: Annual exam and faecal check — every 12 months (every 6 months from 10 years old)
Top resources for more info
Independent creators and organisations we would send a friend to. We have no affiliation with any of them, and nothing here is sponsored. Links checked 2026-09-19.
YouTubers
Leopard GeckoLeopard and crested gecko care, setups and healthReptiles and ResearchEvidence-led husbandry: enclosure size, UVB, thermal gradients, enrichmentClint's ReptilesWhich reptile suits you, with honest care and handling verdicts
Sites
Go deeper
Diet
- Day geckos are omnivores.
- Feed gut-loaded, calcium-dusted live insects such as crickets, dubia roaches and locusts several times a week, sized no larger than the space between the eyes.
- Alongside insects, offer a commercial day-gecko nectar or a crested-gecko-style fruit diet a couple of times weekly to mimic the pollen, nectar and soft fruit they take in the wild.
- Supplement with calcium and vitamin D3 on a regular schedule to support their fast metabolism and coloration.
- Provide fresh water, though they mostly lap droplets from misted leaves.
- A varied insect-and-nectar diet prevents the deficiencies seen on insects alone.
Health
- Healthy day geckos are vividly coloured, alert and quick, with clear eyes and a good appetite.
- Their skin is fragile and tears easily, sometimes leaving permanent scars, so they should be handled as little as possible.
- Calcium deposits, metabolic bone disease from poor UVB or supplementation, and retained shed are the main concerns.
- Dull colour, lethargy, weight loss or a swollen jaw signals a problem and warrants a vet experienced with exotics.
- Because they bask in strong light, correct UVB and a proper thermal gradient are central to preventing the most common illnesses.
Is your enclosure big enough?
Minimum floor area2,030 cm² (315 sq in) of continuous, unbroken floor
As dimensions45 x 45 x 60 cm
Height60 cm minimum. This species climbs, so height is not optional.
CompanyMust be housed alone. Solitary; house singly
Is this urgent?
Small geckos dehydrate and lose condition quickly, and the tail is the fuel gauge.
Go now
Tremors, weak grip, or a jaw that will not close properlyGo now. Calcium and D3 deficiency.
NowToday
Tail visibly thinning in a species that stores fat thereWeigh, then call with the trend. The fat store goes before the body condition does.
TodayStuck shed around the toes or over the eyesRaise humidity, offer a damp hide, and call if it is not clear within a day. Constricting shed rings cost toes. This is the most common avoidable injury in geckos.
TodayRefusing food with weight lossCheck the cool-end and warm-end temperatures, then call. A gecko that cannot reach its preferred temperature cannot digest.
TodayThis is general guidance for a healthy adult, not a diagnosis. An exotics vet who knows your animal always overrides it — and the time to find one is before you need one.
Can a madagascar giant day gecko eat that?
Geckos split into two diets that share almost nothing: insectivores like the leopard gecko, and the fruit-and-insect species like the crested gecko. Check which one you have.
The full list
Never (13)
AlcoholNo safe amount at any body weight on this site.
neverAvocadoPersin.
neverCaffeineCoffee, tea and energy drinks. Cardiac and neurological toxicity at tiny doses for an animal this size.
neverChocolateTheobromine and caffeine. Small mammals and reptiles cannot clear either.
neverCitrusAcidic, and it blocks calcium absorption.
neverFirefliesLucibufagins. Fatal to geckos.
neverGarlicSame allium toxicity as onion, and more concentrated by weight.
neverInsects larger than the gap between the eyesA recognised cause of impaction and neurological injury in small geckos. Size the feeder to the animal, every time.
neverLeekAllium family. Same mechanism as onion and garlic.
neverOnionOrganosulphur compounds damage red blood cells. The whole allium family is out.
neverRhubarbVery high in soluble oxalate, high enough to cause acute kidney injury. The leaves are worse than the stalks.
neverSalty or seasoned human foodSalt, oil and seasoning. Crisps, chips, seasoned leftovers and processed meat are all out.
neverWild-caught insectsPesticides and parasites.
neverRare treats (1)
WaxwormsVery fatty and habit-forming. Useful to get weight on a thin animal. One or two, rarely.
rare treatOccasional (4)
HornwormsHigh water content; useful for a dehydrated animal. One occasionally.
occasionalMashed fruitFor crested and gargoyle geckos only, and only as a supplement to a complete diet. Never for a leopard gecko. A small amount, alongside the complete diet.
occasionalMealwormsHard chitin and a poor calcium ratio. A leopard gecko fed only mealworms is a leopard gecko heading for calcium problems. A few alongside better feeders.
occasionalSuperwormsFatty. One or two.
occasionalEveryday foods (4)
Black soldier fly larvaeHigh in calcium, and readily taken. Several per feed.
everyday foodComplete crested gecko diet powderFor crested, gargoyle and chahoua geckos only, mixed with water. A complete food and the simplest way to feed those species correctly. Fresh, every other day, for fruit-eating species.
everyday foodCricketsStandard feeder. Gut-load for 24 hours before offering. Sized to the eye gap.
everyday foodDubia roachesThe best routine feeder for insectivorous geckos. Sized no wider than the space between the eyes.
everyday foodThat food is not on our list. Check which kind of gecko you have first — the two diets barely overlap — then ask an exotics vet.
Dust feeders with calcium to the schedule in the species guide, and keep a small dish of plain calcium available for insectivorous species.
What it really costs
Setup, monthly, first year and across a whole life, itemised and with the electricity worked out from the actual wattage. Published figures for the same animal disagree by a factor of four, so the calculator shows ranges rather than picking one.
Bedding and substrate
Match the substrate to the species' humidity, and never let a small gecko stand on anything it can swallow whole.
Safe
Topsoil and play sand mix for arid geckosPacks firm, holds a burrow, and is what a leopard gecko would actually stand on.
safeCoco fibre and orchid bark for tropical geckosHolds the humidity a crested or day gecko needs.
safePaper towelCorrect for quarantine, for hatchlings, and for any animal whose output you are watching.
safeWith a caveat
Sphagnum mossExcellent in a humid hide, poor as a whole-floor substrate — it stays wet.
with a caveatNever
Calcium sandSold as digestible, which is exactly why it gets eaten. Implicated in impaction.
neverCrushed walnut shellSharp and indigestible.
neverLoose play sand alone for hatchlingsToo easy to swallow at that size.
neverA humid hide is not optional for most geckos, whatever the main substrate is. Most stuck-shed problems trace back to its absence.
Compare with other animals
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