Oreochromis mossambicus are used to control filamentous algae, which is a habitat for mosquito larvae, thus the tilapia is used to help with malaria control. Tilapia are omnivorous and will feed on an artificial diet in addition to the zooplankton in the pond.
Under monoculture conditions, fry (about 1 g) are stocked into nursery ponds and once they reach 30 g are stocked into grow-out ponds.
Stocking density is usually at 1 to 2 fingerlings per m2. The pond is then fertilized to maintain high levels of plankton. Supplemental feeding of an artificial diet will improve production. With fertilizing and supplemental feeding, the pond can be harvested after six months and will yield between 1500 and 4000 kg of fish per hectare per year (750-2000 kg per harvest).
At harvest, the percentage of the total pond fish weight is around 70%, with the remaining 30% made up of fry and fingerlings. These smaller fish can be kept back from harvest and added to the pond during the next production cycle.
A yearly production of 15-40 kg of fish in a
100 m2 pond may not seem like much; however, if it feeds a fish farmer and his/her family, this extra protein is of great nutritional benefit.
Catfish has a high dietary protein requirement and therefore feeding with a formulated
feed is a prerequisite for intensive culture of the species. Optimal growth rates and food conversions are achieved with diets containing 35-42% crude protein. The artificially formulated diets are composed of vegetable and animal feedstuffs that are supplemented with vitamins and minerals.
It is difficult to give a standard formulation for a balanced diet for catfish as the composition of the formulated diets depends on the availability and prices of locally available feedstuffs. In order to help acclimatize the fish to the feed and feeding place in static ponds, slightly higher feeding levels may be applied during the first three months. However, due to deteriorating water quality, lower feeding levels should be applied during the last three months of culture. After about six months the pond can be harvested, with a net production of 4-8 tons/ha.