Freshwater prawn, also called Malaysian prawn, are the species Macrobrachium rosenbergii, originally from Malaysia. These are relatively easy to aquaculture, but require large ponds with excellent filtration and water quality. Many prawn farms have successfully employed a three-pond grow-out system, allowing for three harvests a year. Unlike its saltwater counterparts, it is unnecessary to be concerned with salinity. However, many of the water-quality issues are the same. Raising freshwater prawn in tanks has generally been unsuccessful, as these animals need well-oxygenated water and plenty of space to thrive.
Obtain proper permits and/or licenses if you intend to sell farmed prawns. Laws will vary according to your location and the size of your operation.
Prepare your grow-out pond or ponds. Ponds must be in an area not prone to flooding and unaffected by runoff from areas utilising pesticides. Ponds should have a depth of half a metre to a metre and half (2 to 5 feet) and a surface area of 1 to 5 acres. Employ skimmers, filters and aerators to keep the water quality optimal. Fertilising the pond will ensure plenty of natural food for the prawns in the form of algae. The pond should maintain a temperature of at least 21.1 degrees Celsius and a pH between 6.5 and 9.5.
Purchase juvenile prawns from a hatchery. Hatching is the most difficult part of prawn farming and should not be attempted by individuals without extensive knowledge of prawn biology and brackish water quality maintenance.
Acclimate the prawns to their new environment. Slowly replace the water they were transported in with water from the grow-out pond.
Stock the first grow-out pond. M. rosenbergii are aggressive, and a hierarchy is formed among males. Stocking densities need to be kept low to prevent cannibalism and stunted growth. The pond should allow for at least 4 square metres per prawn. Lower densities result in larger shrimp.
Feed the prawn once they reach 5 grams. Smaller prawn will receive enough nourishment from small pond organisms. A pelleted feed of at least 38% protein works well. Prawn can be fed twice daily, with a larger feeding at dusk, as shrimp are nocturnal.
Be certain there are no fish, turtles, or frogs living in your pond, or your prawn will become their dinner.
Farmed prawn are susceptible to a variety of bacterial and fungal disease.