must agree with lotus. with all the new "fabulous" colors of the livebearing families, i'd say that, if you retraced their routes, you'll bound to find some incest. they do this to maintain the color and tail patterns. like a lyretail molly for example, has been inbred a lot. these inbreeding tactics apply to almost every fish you can imagine, from bettas to rams, angelfish to discus, its not that nasty if you think about...