This work is a contribution to the project Aquaculture: Increasing Income, Diversifying Diets and Empowering Women in Bangladesh and Nigeria. The objective of this document is to provide basic information on managing water quality in freshwater fishponds in Bangladesh to support farmers in profitable, sustainable aquaculture practices. The rapid development and intensification of freshwater aquaculture in Bangladesh has resulted in new challenges for managing pondwater quality. Enhancing fish production means a larger fish biomass per unit volume and more decaying organic waste to control. As a result, pond management techniques need to be adapted to maintain optimal water quality parameters. Understanding and managing the oxygen budget in fishponds is essential to optimize production.