Hanoi, the capital of Vietnam, is one of the most densely populated areas in the world, with about 3,000 people km-2. Traditionally, aquaculture is practiced in ponds, reservoirs and urban lakes, rice fields, wastewater and VAC [an acronym from the Vietnamese words for garden (vuon), pond (ao) and livestock quarters (chuong)] systems. With over 5,000 ha of surface area and 3,000 ha of lowland rice fields, Hanoi has potential for further aquaculture development and tourism-entertainment services. The importance of aquaculture has long been recognized as a source of income and employment. Nowadays, pond aquaculture in peri-urban areas is decreasing due to urbanization, while in areas far from the city it is increasing through the conversion of lowland rice fields to fish ponds.