Mexican axolotl (Ambystoma mexicanum). The axolotl species naturally occurs in various color morphs, including wild-type (with dark speckled pigmentation), leucistic (white or pale pink), golden albino (yellow or gold with pinkish tones), and melanoid (solid black or dark brown).
However, it's worth noting that breeders and enthusiasts often use the term "copper" to describe axolotls with a unique coloration that appears coppery or metallic. These axolotls may exhibit shades of brown, orange, or reddish hues, resembling the color of copper. It's important to understand that this is not a recognized axolotl morph but rather a term used to describe an individual axolotl's specific coloration.
If you come across an axolotl referred to as "copper," it's likely a descriptive term used to convey its unique color rather than a distinct genetic variant. It's always fascinating to observe and appreciate the diverse range of colors and patterns that axolotls can exhibit, but it's essential to differentiate between recognized morphs and individual variations in coloration.