This book is a comprehensive guide designed for fish farmers, aquaculture entrepreneurs, extension workers, and students involved in aquatic farming. It focuses on one of the most critical aspects of aquaculturewater quality managementand explains how proper monitoring and maintenance of water parameters can lead to healthy, productive, and profitable fish farming operations.The manual introduces and explains twenty-one essential water quality parameters, classified under physical, chemical, and biological categories. These include temperature, dissolved oxygen, pH, salinity, ammonia, nitrate, nitrite, and moreeach of which plays a vital role in the growth, health, and survival of cultured fish species. The book outlines the importance of each parameter, its ideal range, causes of fluctuation, and practical methods for testing and analysis.Special attention is given to helping new farmers and entrepreneurs understand the scientific basis behind water quality, while also offering hands-on methods that are cost-effective and easy to implement. By following the recommendations in this manual, farmers can ensure optimal pond conditions, reduce losses, and increase production sustainably.This book aims to bridge the gap between scientific knowledge and field-level application, making it an essential resource for anyone involved in aquaculture.