This is one of ten eBooks on the commercial production of ornamental fish. It is based predominantly on the author's 30 years of experience, mostly on his own farms. While a few of the eBooks are purely commercial, others, particularly those on breeding, will also be helpful to hobbyists, understandable even by beginners. The following description is provided as a guide. Comprehensive section on essential aspects of fish-oriented water chemistry. Includes methods and chemicals for managing water chemistry on fish farms, and for breeding, with methods for softening, hardening and buffering water, and adjusting pH etc. Predominantly commercially oriented, but with many aspects of interest to serious hobbyists.