Constructed wetlands have emerged as a sustainable and efficient approach for treating wastewater, offering numerous environmental and economic benefits. This chapter examines the design, operation, and performance of contracted wetlands as a viable solution for wastewater treatment especially in fishery sector. The design aspect highlights the critical factors considered during the planning phase of constructed wetlands. It discusses the selection approaches of appropriate wetland types, such as free water surface (FWS) and subsurface flow (SSF), based on specific pollutant removal requirements and available land space. Factors such as hydraulic retention time (HRT), vegetation type and layout configuration are examined in the context of maximizing treatment efficiency and ensuring successful integration into the fishery environment. The operation section delves into the practical implementation and management of constructed wetlands for wastewater treatment in the fishery sector. It explores the importance of regular monitoring and maintenance to sustain optimum performance. The significance of understanding wetland ecology and the roles of microorganism and aquatic plants in pollutant removal are also discussed, highlighting the importance of ecological balance within the system. The performance assessment of constructed wetlands focuses on their removing various pollutants commonly found in water, organic matter, and potentially harmful substances. Moreover, this chapter discusses the environmental effect or benefits of constructed wetlands, such as habitat creation and biodiversity enhancement, which can contribute to the overall structure of promoting a healthy fishery ecosystem. The potential economic advantages are also discussed in this chapter. Overall, this provides valuable insights into design, operation, and performance of constructed wetlands for wastewater treatment in the fishery sector. Understanding the critical factors involved in their implementation and their capacity to improve water quality can contribute significantly to sustainable development in the fishery industry, ensuring both environmental protection and economic viability.