At a glance: Day gecko morphs are mostly named locale lines and color forms, not single gene mutations. No peer reviewed study has tested the inheritance of any named Phelsuma morph. Every inheritance entry below is labeled as untested unless a paper backs it.
Day gecko morphs are captive color forms of the genus Phelsuma. These diurnal, mostly green geckos come from Madagascar and nearby islands. Unlike leopard geckos, day geckos have no verified list of single gene morphs.
There are no documented recessive albinos or incomplete dominant patterns. What hobbyists call a morph is usually a locale line, a subspecies form or a selectively bred variant.
This page indexes day gecko morphs and lines. It separates what the literature documents from what breeders report, so you can read a listing without guessing. For the species themselves, see the day gecko species list.
What counts as a morph in Phelsuma
In the reptile hobby, a morph is a heritable color or pattern variant with a name. In the best studied groups, the name comes with a tested inheritance mode: recessive, dominant or incomplete dominant. Day geckos lack that test data.
The peer reviewed work on Phelsuma color covers natural variation between species, not captive mutations. Saenko and colleagues examined five species: Phelsuma klemmeri, Phelsuma quadriocellata, Phelsuma lineata, Phelsuma laticauda and Phelsuma grandis. That study describes how the colors are built, which sets the limits for what a color morph could change.
For the general idea of morphs across all reptiles, the morph database is the front door.
Punnett square basics live on the morph genetics page.
How Phelsuma color works, and why it matters for morphs
Day gecko skin stacks three cell types. From the surface down, they are xanthophores (yellow) or erythrophores (red), iridophores holding guanine nanocrystals, and melanophores (dark). Saenko and colleagues (2013) found that blue and green come from ordered multilayers of guanine nanocrystals in the iridophores.
The green you see is blue structural color filtered through yellow pigment. A white belly comes from disordered crystals that scatter all wavelengths. Red markings come from pteridine pigments, which shift toward yellow with lower pH or with oxidants in lab tests.
This matters because a blue day gecko can arise several ways. Losing the yellow filter leaves blue. Losing red pigment removes the markings.
Phelsuma klemmeri does this naturally, with a blue or brown background and no red. A listing that says “blue” says nothing about inheritance. The day gecko colors guide covers the mechanism and color change in full.
Named day gecko morphs and lines index
The table lists every form this page can verify as existing in some documented sense. No row has a tested inheritance mode.
Where a source documents only natural variation, the row says so. Otherwise the label reads: hobby name, inheritance reported by breeders, not independently tested.
| Form | What it looks like | Inheritance | Source or label | Known health issues |
|---|---|---|---|---|
| Wild type Phelsuma pattern | Blue or green dorsolateral background with red dorsal markings | Species level trait, not a morph | Saenko et al. 2013 | None documented in this source |
| Phelsuma klemmeri natural form | Blue or brown background, no red markings | Species level trait, not a morph | Saenko et al. 2013 | None documented in this source |
| Phelsuma laticauda subspecies (laticauda, angularis) | Subspecies forms of the gold dust group | Subspecies, not a morph | Animal Diversity Web lists both infraspecies | None documented |
| Phelsuma madagascariensis subspecies: madagascariensis, boehmei, kochi and grandis | Bright green giant day geckos, regional forms; kochi is the Koch’s giant day gecko of the northwest | Subspecies (three proposed as full species), not a morph | D’Cruze et al. 2009, citing Raxworthy et al. 2007 | None documented |
| Named giant day gecko lines (high red or crimson, blue) | Breeder names for stronger red markings or a bluer body tone | Unknown | Hobby name, inheritance reported by breeders, not independently tested | None sourced |
| Other captive color lines (selective breeding of bright or reduced marking animals) | Varies by line | Line bred or polygenic, presumed | Hobby name, inheritance reported by breeders, not independently tested | None sourced |
Read the last two rows carefully. “Line bred” here means breeders keep choosing the brightest animals over generations.
That can shift color without one identifiable gene. It may explain many named lines, though no study confirms it.
Giant day gecko morphs and captive lines
Giant day gecko morphs are the best known day gecko lines in captivity. The animal is Phelsuma madagascariensis, and the form most often kept is the subspecies Phelsuma madagascariensis grandis.
The Animal Diversity Web account gives a length of up to 25 cm. The body is bright green, from light to bluish green.
It also lists a rust or red stripe from the nostril to behind the ear. Brown dots run along the mid back, and blue rings circle the eyes.
Males are more vividly colored with larger heads. Juveniles look like adults but have orange undersides on the tail.
D’Cruze and colleagues (2009) report a maximum total length of 300 mm for Phelsuma madagascariensis grandis, the largest gecko in their survey. They list four subspecies: madagascariensis on the east coast, boehmei around Andasibe, kochi in the northwest and west, and grandis in the north.
Raxworthy and colleagues (2007) proposed raising madagascariensis, grandis and kochi to full species and sinking boehmei into the nominate form, which is why Saenko and colleagues write Phelsuma grandis. The two size figures differ because one covers the species and the other the subspecies.
Because of that taxonomy, many “giant day gecko morphs” are really wild locale forms. A subspecies name is a different claim from a new mutation. Only the first can be checked against a range, and only for the wild lineage.
The “Koch” giant day gecko is therefore kochi, a wild lineage, not a captive morph. Named high red, crimson and blue lines are the giant day gecko morphs breeders discuss, and no authoritative source documents their inheritance.
Treat those color lines as hobby names. For the parent species, see the giant day gecko care overview.
Gold dust and other Phelsuma color forms
The broad-tailed day gecko, Phelsuma laticauda, has two recognized infraspecies, laticauda and angularis, per the Animal Diversity Web classification. Saenko and colleagues included it and found pigmentary and structural elements sitting in the same skin regions. No captive morph of this species is documented in the peer reviewed record.
The rest of the genus is similar. Species differ in which chromatophore layers are present and how they stack.
That is species level variation. The species list owns those comparisons, and this page does not repeat them.
Health and genetics: what is and is not known
No health problem has been sourced to any day gecko color form in the literature reviewed for this page. That is an absence of evidence, not proof of safety.
Breeders report health linked traits in some other gecko groups. Those reports do not transfer to Phelsuma.
Sex determination matters for breeding plans. In the leopard gecko and the African fat tailed gecko, sex depends on incubation temperature (Valenzuela 2004).
Gamble and colleagues (2015) found XY and ZW systems across 12 gecko species. The system in day geckos is not sourced here, so do not assume either.
How to judge a morph claim
Ask for the pedigree of any day gecko morph, not the label. A tested recessive trait produces predictable offspring in pairings that a breeder can document. An untested line gives no such record.
Check five things before treating a name as a genetic trait:
- Whether the seller gives the parents and their lines for at least two generations.
- Whether the color holds in offspring raised at normal temperatures and diets.
- Whether the name refers to a wild locale or subspecies instead of a mutation.
- Whether any tested inheritance mode is stated, or only “reported.”
- Whether the animal shows normal eyes, skin and growth.
Pressure or dehydration changed structural color in experiments on Phelsuma skin. A dull animal is not a different morph. If a gecko’s color changes abruptly, a reptile veterinarian should examine it.
For other gecko groups, see the gecko morphs index.
Frequently Asked Questions
Are there recessive day gecko morphs?
None is documented in the peer reviewed record. Breeders may report recessive traits, but those claims are hobby names with inheritance reported by breeders, not independently tested. Buyers should ask for pedigrees.
Why are so many day geckos green or blue?
Blue comes from ordered guanine nanocrystals in the iridophore layer. Yellow pigment above that layer filters the blue, which produces green. A gecko with less yellow can look blue.
Is the Koch giant day gecko a subspecies?
Yes. D’Cruze and colleagues (2009) list Phelsuma madagascariensis kochi from northwest and west Madagascar as one of four subspecies, and Raxworthy and colleagues (2007) proposed treating it as a full species. It is a wild lineage, not a hobby morph.
Can a day gecko change color quickly?
Not much. Saenko and colleagues found limited evidence for rapid pigment movement. Pressure or dehydration shifted structural color in experiments by changing nanocrystal spacing.
Do brighter day geckos have more health problems?
No source links brightness or a named line to a health problem in Phelsuma. Poor husbandry is the usual reason a gecko looks dull. A veterinarian who treats reptiles can check an animal that looks unwell.
Where can I learn how morph inheritance works?
Start with the morph genetics page, which explains recessive, dominant and incomplete dominant traits with Punnett squares. Apply that only to traits that have been tested.
Sources
- Saenko SV et al.: Unraveling the mechanisms of color pattern in Phelsuma, BMC Biology 2013. https://bmcbiol.biomedcentral.com/articles/10.1186/1741-7007-11-105
- Animal Diversity Web: Phelsuma madagascariensis. https://animaldiversity.org/accounts/Phelsuma_madagascariensis/
- Animal Diversity Web: Phelsuma laticauda classification. https://animaldiversity.org/accounts/Phelsuma_laticauda/
- D’Cruze N et al.: Phelsuma madagascariensis grandis, Herpetological Conservation and Biology 2009. https://www.herpconbio.org/Volume_4/Issue_1/D’Cruze_etal_2009a.pdf
- Gamble T et al.: Restriction site associated DNA sequencing of gecko sex chromosomes, Molecular Biology and Evolution 2015. https://academic.oup.com/mbe/article/32/5/1296/1130958
- Valenzuela N: Temperature dependent sex determination, Iowa State University 2004. https://faculty.sites.iastate.edu/nvalenzu/files/inline-files/valenzuela2004_reptiliantsd_chapt09.pdf