This book explains how the beautiful goldfish body develops from a single fertilized egg and how this developmental process was changed during the process of domestication. The contents can be categorized as follows: i) numerous high-quality live photo images of embryonic and larval stage goldfish, ii) detailed descriptions of skeletogenesis with fluorescent microscopic and histological images, iii) the most advanced interpretation of the relationship between artificial selection and developmental processes, iv) future perspectives of the application of the genome editing techniques for the ornamental goldfish breeding, and v) methodological descriptions for goldfish developmental biology. Goldfish is a popular ornamental domesticated fish species, and its highly diverged morphological features and color variations attract fanciers. The goldfish has been spread all over the world by breeders, and this fish has also been employed as an experimental organism by researchers in the field of life science. However, so far, no available scientific books provide a detailed description of the embryogenesis and morphogenesis of this animal. Compared with the number of published fancier books, the number of books on goldfish biology is very few. This publication will be useful not only for the research community particularly in the fields of developmental biology, evolutionary biology, zoology, aquaculture, fishery science, and related areas but also for enthusiastic goldfish fanciers and breeders.