The demand for fish in Sub-Saharan Africa, as driven by the trend of diet-shift to fish, economic and demographic growth, outstrips supply. The resulting fish deficit is drawing attention of policy makers as it poses threats to economic stability as well as food security in the region. In this paper, a multi-species, multi-sector equilibrium model is developed and applied to Zambia as a case study to provide a tool for policy makers to examine the interaction between fish supply and demand.