To determine how best smallholders could maximize the profitability of their catfish hatcheries, the cost/benefit analyses of using fences, hapas and bird nets to exclude predators; as well as over-stocking to create food shortage, were conducted. As compared to the typical production system (fertilized unfenced ponds) and at a stocking density of 10 two-day old fry/m2, survival increased by 28% in fenced ponds, 34% in open hapas and 55% in bird-netted hapas. These increases were believed due to the respective exclusion of adult amphibians, aquatic insects and flying predators, implying that they would be respectively responsible for 28%, 6% and 23% of the fry mortality which was observed in unfenced ponds.When the stocking density of closed hapas (predator-free systems) was increased from 10 to 40 fry/m2, fry survival significantly dropped (P