This paper is an impact study of key short- and long-run effects of the Danida supported Mymensingh Aquaculture Extension Project (MAEP) in Bangladesh, applying different matching and double difference estimators. Results are mixed. First, the paper finds a positive short-run impact on pond productivity and the value of fish production per capita among participants. However, in the long run no similar well-determined effect emerges. Second, MAEP appears to have had no significant impact on socioeconomic status as measured by consumption expenditure of participating households. The authors argue that these results are closely linked to non-favourable developments in the output price and the fact that agricultural production, including rearing of livestock and service sector employment (self or wage employment), are much larger sources of income than fish pond production.