Synopsis Biotechnology is a technique that used living organisms to create and amend a product, to develop plants and animals or to develop microorganisms 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 utilization 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 hybridization methods.  Aquaculture is multidisciplinary activity.  This book overviews Fishes and related biotechnology techniques.  The following are some chapters which are included in this book.  cytogenesis of Fishes, Biochemical and Molecular Genetics, Genome manipulation in Fish, Hybridroma Technology, Algal Biotechnology, Microbial Biotechnology for Aquaculture, Health Management and Modern Technology in Aquaculture.  Reading of this book will be beneficial for students of fisheries, researchers in this field and entrepreneurs.