siamese fighting fish at top of tankResults found out that the double tail, elephant ear, albino, and fin spot mutants each were determined by single major effect loci. The elephant ear phenotype was likely associated with differential expression of a potassium ion channel gene, kcnh8. The albinotic phenotype was likely linked to a cis regulatory element performing on the mitfa gene and the double tail mutant was suggested to be caused by a deletion in a zic1/zic4 coenhancer. Our data spotlight that major loci and cis regulatory elements play vital roles in bringing about phenotypic strategies and set up Bettas as new effective model to study the genomic basis of developed changes. Already in the “On the Origin of Species” 1859 and later in the “The Variation of Animals and Plants under Domestication” 1868, Charles Darwin recognized that an identical tactics of preference that act in nature also apply to selective breeding where they are accelerated orders of magnitude by breeders’ goals to obtain certain traits. Obviously, Darwin couldn’t know the genomic basis that underlies the specific traits.