The book entitled “The Feed Additive and The Fish” is an endeavor to evaluate the ameliorative influence of locally available, low cost feed additives on commercially important fishes; to encourage fish culturist to promote use of these additives which might be a rich source of protein, fat and minerals, essential for human health, and to increase income and livelihood from ornamental fish trade (at some extant) by incorporating this type of low cost feed additives. Supplementary feeding plays important role in augmenting aquaculture productivity and its cost is the major operating expenditure. Hence, to reduce reliance on the expensive conventional feed ingredients, less expensive alternative source of quality proteinous ingredient must be explored. Impact on growth, pigmentation and nutrient profile of three fishes fed on diets with five different natural feed additives were experimentally verified and reflected in this book. Significant improvement in growth and protein content with enhanced pigmentation in case of one additive, while only on fish pigmentation in case of other is noticeable.