Biotechnology is a technique that used living organisms to create and amend a product, to develop plants and animals or to develop micro-organisms for explicit uses. Biotechnological means of genetic improvement is a modern and faster approach. Genome manipulations (Chromosomal Engineering) and gene transfer (Genetic Engineering) have been experimentally studied throughout past in many countries. To date genetic progress in livestock breeding programmes has relied whichever on breed exchange or leading the conventional quantitative genetic approach of testing and selection. Under these circumstances the need to develop new technologies became imperative unlike in agriculture and veterinary farming exploitation of genetic potentials and utilisation of genetically improved cultured varieties of fish is not a common practice in aquaculture all most all species of fish are genetically improved to the traditional selective reading and hybridisation methods. Aquaculture is multidisciplinary activity. This book overviews Fishes and related biotechnology techniques. Reading this book will be beneficial for students of fisheries, researchers in this field and entrepreneurs.