The term "wild type" is used to refer to the most common characteristic of a species under natural conditions, without displaying any defining genetic mutations. Wild type axolotls are typically brownish/greyish and can sometimes have a slightly greenish tint. Wild type axolotls will always have a gold eye ring surrounding a black pupil. They contain melanophores, xanthophores, and iridophores.

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Note: The most surefire way to distinguish wild types from copper axolotls is the fact that all copper axolotls will have a red pupil when light is shined on it, while wild type pupils will stay black.

Leucism is a genetic mutation which causes white, pale, or patchy coloration in skin, hair, and nails but not the eyes. In axolotls this is caused by a damaged or missing version of Edn3, a gene that codes the protein Endothelin-3 that tells the chromatophores to migrate from the neural crest and spread across the body as an embryo. 

Leucism in axolotls presents as a white/pinkish body that still has pigmented eyes with xanthophores and melanophores. A normal leucistic will have no melanin on its body other than its eyes, while "dirty leucistic" will have scattered melanin on their face and back. A leucistic axolotl with more melanin on the gill stalks than normal are known as "dark-gilled leucistics".

Albinism is a genetic mutation that results in a partial or complete absence in skin pigment. Albinism in axolotls results in the loss of melanophores. However, xanthophores are still present, resulting in their yellow coloration. Albino axolotls can also have iridophores.

Melanoid axolotls completely lack iridophores and some xanthophores. This results in increased melanophores (dark coloration) on the whole body, as opposed to only scattered spots in wild types and other morphs. This causes melanoid axolotls to have very few spots.

Note: Melanoid and Axanthic are the only two morphs that can never have iridophores or eye rings.

Copper is a form of albinism, resulting in partial loss of pigment. Copper axolotls lack the enzyme, Tyrosinase, that normally oxidizes pheomelanin (responsible for red pigmentation) into eumelanin (responsible for dark coloration). Without this enzyme, they are unable to "convert" red pigmentation into darker pigmentation. This results in their spots of orange pigmentation, rather than the dark brown spots of a wild type. It also results in their inability to produce fully black pupils, thus resulting in their characteristic red reflective ones. Copper axolotls may have iridophores.

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Note: The most surefire way to distinguish wild types from copper axolotls is the fact that all copper axolotls will have a red pupil when light is shined on it, while wild type pupils will stay black.

Axanthicism is a genetic mutation that causes animals to be unable or only partially able to produce xanthophores (yellow pigments). In axolotls, axanthicism results in a loss of xanthophores and iridophores. This results in their characteristic greyish color, along with spots of melanophores (dark pigments) all over the body. Axanthics only very rarely have a reflective eye ring. Axanthic axolotls will show face fluorescence, which can be seen as the connective tissue in their head and limb joints glowing green under blue/black light.

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Note: Melanoid and axanthic are the only two morphs which almost never have reflective eye rings

The hypomelanistic gene causes axolotls to produce much less melanin than usual. Xanthophores and iridophores are unaffected, however, which causes these axolotls to appear as a yellowish color. 

GFP axolotls were first modified in the lab, where fluorescent jellyfish genes were inserted into their genome. After this, the genes were then able to be passed down through breeding, thus giving us all the GFP axolotls we see today. The GFP gene enables the axolotl to absorb short wavelengths of light, like blue and black light, and emit green light as a result. This causes GFP axolotls to glow green under blue and black light.

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White albino axolotls will have a complete lack of melanophores, iridophores, and have a damaged or missing Edn3 gene, which prevents the chromatophores from spreading from the neural crest. Due to this, xanthophores can only be present on the gills and down the spine. 

White axanthic axolotls will have a complete lack of xanthophores and only have melanophores in the eyes and gill stalks. They can potentially have iridophores in the eyes. 

Leucistic copper axolotls will have light eyes and a red pupil. If the axolotl is dirty, its dark spots would be a chocolate brown color instead of black. 

Melanoid albino axolotls lack melanin, iridophores, and have a reduced amount of xanthophores. The resulting color is a slight yellow tint. 

Sometimes referred to as “lavenders” by breeders, melanoid axanthic axolotls appear to have a purple-ish tint at a very young age. However, most morphs will darken significantly as they age, and melanoid axanthic axolotls will end up with a darker color, like a dark melanoid or wild type axolotl in adulthood. These axolotls lack xanthophores and iridophores, but have a dense distribution of melanophores.

Melanoid axolotls have almost a complete lack of iridophores and produce pheomelanin. Due to the melanoid gene, they would have little if any spots.

Albino axanthic axolotls would have a complete lack of melanophores and xanthophores, causing them to be fully white. Keep in mind that over time axanthics gain yellow pigment due to their diet.

Albino axanthic axolotls would have a complete lack of melanophores and xanthophores, causing them to be fully white. Keep in mind that over time axanthics gain yellow pigment due to their diet.

Appearance is indistinguishable from Albino (Golden albino).

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Melanoid axanthic coppers, often referred to as MACs, possess all three of these recessive morph genes. MACs and melanoid coppers are nearly indistinguishable, except for at a young age when the skin cells are more easily observable. At a young age, it will be apparent that MACs lack yellow xanthophores, while melanoid coppers do have them.

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The following albino three gene combinations are indistinguishable from white melanoid albino axolotls:

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White Melanoid Albino

White Albino Axanthic

White Albino Copper

Melanoid Albino Axanthic

Melanoid Albino Copper

Mosaicism is a genetic mutation that takes place during the embryonic development of the axolotl egg. As the egg cell first begins to divide into more cells, a specific error occurs, resulting in the coding of two sets of dominant genes in one body, which often results in two different morph colors as well. The earlier that this mutation takes place during the development of the egg, the more split the coloration will appear on the axolotl.

For example, the mutation occurring during only the first couple divisions of the egg will result in an axolotl with almost completely split coloration. When the mutation occurs later on, then the resulting axolotl will have a more mottled appearance in coloration.