The axolotl, Ambystoma mexicanum, is an aquatic salamander recognized for its neotenic characteristics, meaning it retains its larval features throughout its life. This creature does not typically undergo metamorphosis to live on land. The axolotl is available in a wide array of color variations, known as morphs, which are the result of naturally occurring genetic differences and selective breeding. The copper axolotl is one such morph that has gained popularity among hobbyists for its warm coloration.
Appearance and Identification
The copper axolotl is distinguished by its light brown, tan, or sometimes pinkish-brown body. This base color is often adorned with a dense pattern of darker brown or reddish freckles. These speckles are a result of melanin that has not been fully oxidized, making them appear brighter than the spots on a wild type axolotl.
Unlike the wild type, which has a darker, mottled brown or green coloring and dark eyes, the copper axolotl is much lighter and has red-tinted eyes. It also differs from the golden albino, which usually presents with a more yellow or golden hue and generally lacks the copper’s characteristic freckles. The gills of a copper axolotl are often grayish-red or a similar color to their body, with feathery filaments that can appear pink due to the visible blood vessels.
The Genetics Behind the Color
These axolotls are a form of albino, which means they lack melanophores, the pigment cells responsible for producing black and dark brown colors. Their distinctive hue is not from a single pigment but from the combined expression of other types of pigment cells. Xanthophores contribute the underlying yellow and red tones, while iridophores provide the light-reflecting quality that gives them their signature coppery sheen.
This specific combination of traits is the result of recessive genes. For an axolotl to express the copper phenotype, it must inherit the necessary recessive genetic markers from both of its parents. This genetic requirement is a primary reason why copper axolotls are less common in the hobby compared to more dominant morphs, such as the wild type or the leucistic morph. The condition is considered a less extreme form of albinism because some pigments are reduced but not entirely absent.
Specific Care Needs
Like all axolotls, they require cold water temperatures, ideally maintained between 60-68°F (15-20°C), as warmer water can cause stress and disease. A spacious tank with a low-flow filtration system is necessary to mimic their natural, still-water habitat. Their diet is carnivorous, consisting of items like earthworms, bloodworms, and specialized pellets.
The albinism that gives the copper morph its color also results in poor eyesight. Their red-tinted eyes are sensitive to bright lighting, so provide plenty of hiding spots in the tank, such as caves and dense plants. This reduced vision can also make finding food a challenge.
To ensure a copper axolotl is well-fed, use tongs to present food directly in front of the axolotl to help them locate and consume it without excessive searching. This targeted approach prevents food from going uneaten and fouling the water, which is important for maintaining a healthy aquatic environment.