This section gives a detailed background to some important aspects of fish breeding and commercial production. These include: a look at water and how it supports fish life in the natural environment, basic water chemistry from a fish breeding and farming perspective, an overview of production and general breeding methods for different groups (families) of fish, commercial suitability of major families, identifying the sexes, advice on obtaining breeders, and how to quarantine new breeders. Potentially useful to both hobbyist breeders and commercial producers.