Halloween Crested Geckos
A Halloween is a crested gecko that fires up in two colours only, orange markings over a black or near-black base. Yellow, gold or cream in the pattern rules a gecko out, but breeders disagree over whether any white is allowed.
About the Halloween gene
Halloween refers to a description of colour instead of just one gene. It describes a crested gecko with only two colours, orange and black. Because the classic Halloween is a harlequin, the orange appears on the back, limbs, and sides against a dark base. This contrast is why keepers buy one. The animal is judged better if the colours are tighter.
Appearance
The base should be close to or true black with a plain orange pattern. A gecko moves away from the name if there is yellow in place of the orange or brown in place of the black. Yellow, gold and cream must not show on the body or head, though the belly is left out of that rule. White is where the hobby splits. Some breeders want no white on the animal at all, while others accept a Halloween with portholes, which are the raised patches of unfinished pigment. Ask the seller which standard they work to if the listing photo shows white.
Genetics
Halloween is polygenic. Instead of pairing a single inherited factor, breeders keep the colours by selecting dark, orange-patterned animals over generations. You will see it listed as Halloween and as Pos Halloween. No first year or originator is recorded.