An allele affecting display coloration in the fish, Poeciliopsis viriosa.

The inheritance of an autosomal recessive gene affecting the distribution of yellow xanthrophores on the body scales and fins of P. viriosa is described. Individual males and females having the mutant phenotype, gray, lack the normal olivaceous body coloration. Also, mutant males cannot exhibit the brassy display coloration used by wild-type males in mating and aggressive encounters.