To better understand the key components of aquaculture production in periurban Africa, the farming systems and profitability of five semi-intensive fish culture investments within 35 km of the centre of Yaoundé, Cameroon were subjected to economic analysis. Profitability of farms varied considerably. Two farmers lose money each year. Net returns to management on profitable farms ranged from a low of Fcfa 0.3 million, to a high of Fcfa 3.87 million (overall weighted average = Fcfa 0.99 million). Payback period for the initial investment on farms turning a profit ranges from five to 28 years. Only two farms can be considered solOld_ID investments. Nevertheless, the potential of aquaculture systems to be productive and profitable is apparent from the data collected. It is estimated that the five surveyed farms could increase their production from the current 7.6 to at least 44 tons of fish per annum, returning average profits of Fcfa 21.5 million, if basic principles of fish culture were adopted