Bangladesh has made considerable progress against human development indicators in recent years, but malnutrition resulting from poor dietary diversity and low micronutrient intakes remains entrenched. Fish is central to the Bangladeshi diet and small fish species are an important micronutrient source. Although fish consumption per capita has increased in recent years as a result of rapid expansion of aquaculture, it is likely that consumption of fish from capture fisheries (including small indigenous species particularly rich in micronutrients), has declined. This paper evaluates data on fish consumption collected in Bangladesh by the International Food Policy Research Institute in 1996/7 and 2006/7 to assess changing patterns of fish consumption and their implications for food and nutrition security. This analysis indicates that growth of aquaculture has been positive, mitigating a sharp reduction in the quantity of fish consumed from capture fisheries and smoothing out seasonal variability in consumption. However, increased availability of fish from aquaculture may not have fully compensated for the loss of fish from capture fisheries in terms of dietary diversity, micronutrient intakes and food and nutrition security, particularly for the poorest consumers. A range of approaches are recommended to sustain and enhance the contributions capture fisheries and aquaculture make to food and nutrition security in Bangladesh.