Channel catfish (Ictalurus punctatus) farming is the most economically valuable aquaculture industry in the U.S., with over 200,000 t of fish processed in 1994. Over 70% of the fish were grown in earthen ponds in the Yazoo‐Mississippi River floodplain of northwest Mississippi ("the Delta"). Elements of the physical geography of northwest Mississippi that contribute to the success of channel catfish farming are described in this review. Culture methods and water‐use practices are summarized to provide a framework for a review of the biological and chemical environment of catfish ponds in the Delta. Emphasis is placed on factors of practical importance, including the dynamics of the pond phytoplankton community and the central role of phytoplankton metabolism in pond ecology. The characteristics of pond bottom soils and the nature of catfish pond effluents are also described.