black is there original color, thay are just glorified carp, natural selection favors the dark color,goldfish and koi were bred selectivly just like dogs from the wolf. the turtal showed natural seection in eating the bright ones first!the dark fish have a higher servival rate and also must have a growth gene to grow fast so the smaller preditors dont keepup and than you only have to worry about the big preditors. so ya you must have some comets or koi that have the phynotype of there ansesters.
