original_query: What causes the intensity of color in mature males of Betta splendens?
query: What causes the intensity of color in mature males of Betta splendens?
answer: The intense coloration in mature male Betta splendens is due to the layers of pigmentation in their skin.  These layers, from deepest to outermost, consist of red, yellow, black, iridescent (blue and green), and metallic.  Any combination of these layers can be present, creating a wide variety of colors.