Aquaculture is widely considered to have the potential to reduce poverty and enhance food security. Historically, aquaculture in Bangladesh was a low-intensity, semi-subsistence activity, and most development interventions promoted small-scale forms of aquaculture in the expectation that adoption of improved management practices by low-income households will increase production of fish for sale and home consumption, thereby reducing poverty and food insecurity. This study addresses five research questions about the nature of aquaculture development in Bangladesh. The questions are designed to test central narratives from the literature on aquaculture, poverty, and food security, and to broaden the scope of debate beyond them. The questions are as follows: to what extent do the resource-poor participate in aquaculture?; what is the relationship between participation in aquaculture and landownership and access?; what is the nature and extent of employment associated with different types of aquaculture?; how does aquaculture affect local food security?; and what are the effects of aquaculture development on well-being? An integrated quantitative-qualitative survey was conducted in six communities with contrasting patterns of aquaculture development.