# Freshwater Prawn Farming: Stocking, Shelter, Feeding, and Harvest Management ## Key Takeaways - **Stocking density and grading are critical for growth and survival:** Overstocking leads to cannibalism and stunted growth, while understocking underutilizes pond capacity. Grading prawns by size before stocking and periodically thereafter reduces size hierarchy and aggression, promoting uniformity. - **Shelter is essential to mitigate aggression and facilitate molting:** Freshwater prawns, particularly *Macrobrachium rosenbergii*, are territorial and require refugia such as nets, PVC pipes, or bamboo bundles to avoid predation by conspecifics during their vulnerable molting phase. - **Water quality parameters must be rigorously monitored and maintained:** Optimal conditions include dissolved oxygen above 4 mg/L, temperatures between 26-31°C for *M. rosenbergii*, pH between 7.0-8.5, and total ammonia nitrogen below 1.0 mg/L. Biofloc technology can enhance water quality and feed efficiency but requires careful management. - **Nutritional management and feeding practices directly impact growth and water quality:** Formulated pellets with 30-40% crude protein are recommended, with particle size adjusted to prawn stage. Overfeeding must be avoided to prevent water degradation and disease, with multiple feedings per day improving consumption. - **Humane harvest preparation and biosecurity are paramount for product quality and disease prevention:** Gradual temperature reduction, purging in clean water, and humane slaughter methods (e.g., ice slurry immersion) minimize stress. Biosecurity measures, including restricted access and disinfection, prevent pathogen introduction. - **Veterinary consultation and diagnostic escalation are crucial for disease management:** Prompt investigation of mortality exceeding 5% per week or clinical signs like melanised lesions necessitates veterinary assessment, potentially involving hemolymph or tissue sampling for PCR or histopathology to identify pathogens like *Vibrio* or white spot syndrome virus. --- Freshwater prawn farming requires integration of species-specific stocking density, shelter provision, feeding schedules, water quality monitoring, and humane harvest preparation to achieve productive and sustainable yields. The most commercially relevant species is the giant river prawn *Macrobrachium rosenbergii*, though regional alternatives such as *Macrobrachium nipponense* are farmed in parts of Asia. Success depends on aligning each management decision with the species' biological requirements and the farm's environmental conditions. ## At a Glance | Factor | Key Considerations | Source | |--------|-------------------|--------| | Stocking | Density affects growth, survival, and size uniformity. Grading before stocking reduces cannibalism. | [FAO Animal Production and Health](https://www.fao.org/animal-production/en/) | | Shelter | Required to reduce aggression and provide refuge during moulting. Use substrate, nets, or artificial structures. | [Merck Veterinary Manual](https://www.merckvetmanual.com/) | | Feeding | Use nutritionally complete pellets, adjust ration by stage and water temperature. Avoid overfeeding to maintain water quality. | [PubMed record 42429872](https://pubmed.ncbi.nlm.nih.gov/42429872/) | | Water monitoring | Control temperature, dissolved oxygen, pH, and ammonia. Biofloc technology can improve water quality and feed efficiency. | [Use of biofloc technology in shrimp aquaculture](https://api.elsevier.com/content/abstract/scopus_id/85090473038) | | Harvest preparation | Induce moult synchronisation if needed, use humane methods. Grading before sale reduces stress. | [WOAH Aquatic Animal Health Code](https://www.woah.org/en/what-we-do/standards/codes-and-manuals/terrestrial-code-online-access/) | ## System Context and Planning Decisions Farmers must first select an appropriate production system. Earthen ponds remain the most common approach for *M. rosenbergii* culture, but concrete tanks and raceways are used in areas with limited land or water resources. The choice influences capital cost, biosecurity, and ease of water management. Climate is a critical factor: freshwater prawns require water temperatures consistently above 20 °C for growth, with an optimal range of 28,31 °C. In temperate regions, indoor or greenhouse systems with heating may be necessary, as documented in [USDA APHIS aquaculture guidance](https://www.aphis.usda.gov/livestock-poultry-disease). Market demand and local infrastructure for feed, seed, and processing should be assessed before committing to a production scale. Species planning involves selecting either all-male or mixed-sex populations. All-male culture yields larger, more uniform animals due to reduced agonistic behaviour and differential growth rates. However, sourcing monosex seed requires either manual sexing or hormonal manipulation, which may be restricted in some jurisdictions. The [PubMed record 42250001](https://pubmed.ncbi.nlm.nih.gov/42250001/) reviews growth performance differences between sexes and underscores the need for reliable hatchery supply. ## Core Management Framework Effective freshwater prawn farming rests on five interconnected domains: stocking, shelter, feeding, water monitoring, and harvest preparation. Each domain must be adapted to the specific production cycle,nursery, grow-out, and pre-harvest phases. **Stocking density** directly influences survival and size at harvest. Overstocking leads to stunted growth and increased mortality from cannibalism, especially during moulting. Understocking underutilises pond carrying capacity. Grading prawns by size before stocking is a standard practice to reduce size hierarchy and aggression, as emphasised in the [FAO Animal Production and Health](https://www.fao.org/animal-production/en/) guidelines. Post-stocking, periodic grading (every 3,4 weeks) allows removal of [dominant](/blog/careers/dominant-definition-biology) individuals and re,sorting to maintain cohort uniformity. **Shelter provision** is essential because *M. rosenbergii* is territorial and moults frequently. Juveniles and sub-adults require refugia to avoid predation by larger conspecifics. Options include submerged nets, bamboo bundles, PVC pipes, or artificial substrates. Shelter density should match prawn size and stocking rate. Insufficient shelter increases stress and reduces feed conversion efficiency. **Feeding management** uses formulated pellets with 30,40% crude protein for grow-out. Feed delivery must be adjusted based on daily observation of consumption, water temperature, and moult stage. Overfeeding degrades water quality and encourages disease. The [Use of biofloc technology in shrimp aquaculture](https://api.elsevier.com/content/abstract/scopus_id/85090473038) review describes how biofloc systems can recycle waste nutrients into microbial protein, reducing feed costs and improving water stability. However, biofloc requires careful carbon,to,nitrogen ratio management and aeration. **Water quality monitoring** must include daily checks of temperature, dissolved oxygen (DO), pH, and total ammonia nitrogen (TAN). DO should be maintained above 4 mg L⁻¹. Elevated ammonia and nitrite are toxic, particularly in high,density systems. Aeration, water exchange, or biofloc can mitigate these risks. The [Merck Veterinary Manual](https://www.merckvetmanual.com/) provides reference ranges for common aquaculture species, though specific thresholds should be validated for local conditions. Sudden changes in temperature or pH can trigger moult,related mortalities. **Harvest preparation** requires planning to minimise stress and product loss. Partial harvests (selective removal of market,sized prawns) are common, followed by complete drainage. Inducing a synchronous moult before harvest can improve meat yield but must be timed carefully. Humane slaughter methods, such as immersion in ice slurry or electrical stunning, are recommended in the [WOAH Aquatic Animal Health Code](https://www.woah.org/en/what-we-do/standards/codes-and-manuals/terrestrial-code-online-access/) to avoid unnecessary suffering. Grading and rapid chilling after harvest preserve quality for fresh or frozen markets. Pond design and shelter provision form the foundation of freshwater prawn production. Earthen ponds with a well-compacted bottom and controlled water depth of 0.8 to 1.2 metres are standard. The addition of physical shelters,such as submerged bamboo bundles, nylon netting, polyvinyl chloride pipes, or aquatic vegetation,significantly reduces agonistic interactions and cannibalism, particularly during the vulnerable post,molt period. The [FAO Animal Production and Health](https://www.fao.org/animal-production/en/) guidance emphasises that shelter density should match stocking rate to ensure every animal can find refuge. Substrate complexity also influences growth uniformity, heterogeneous environments allow smaller prawns to avoid [dominant](/blog/careers/dominant-definition-biology) individuals. Water quality management is the critical environmental variable. Dissolved oxygen must be maintained above 4 mg/L, ideally between 5 and 7 mg/L, using paddle,wheel aerators or diffused aeration systems. Temperature for giant river prawn (*Macrobrachium rosenbergii*) should remain between 26 and 31 °C, while the oriental river prawn (*M. nipponense*) tolerates slightly cooler ranges. Total ammonia nitrogen should be kept below 1.0 mg/L, with nitrite below 0.1 mg/L. The [WOAH Aquatic Animal Health Code](https://www.woah.org/en/what-we-do/standards/codes-and-manuals/terrestrial-code-online-access/) provides surveillance guidelines for notifiable crustacean diseases, and farmers should integrate regular health inspections with water testing. pH should be maintained between 7.0 and 8.5, sudden drops can be corrected with agricultural lime, but dosage must be determined by alkalinity testing. Practical monitoring involves daily measurement of temperature, oxygen, and pH, with weekly checks on ammonia, nitrite, and alkalinity. When parameter deviations persist, consultation with an aquaculture veterinarian or local extension specialist is advised. Nutrition and feeding strategies directly affect growth rate and feed conversion. Formulated sinking pellets containing 30,40 % crude protein are commonly used for *Macrobrachium* species. Feed particle size must be adjusted as prawns grow: fine crumbles for post,larvae, 2,mm pellets for juveniles, and 4,mm pellets for adults. The review presented in “Freshwater prawn farming: Global status, recent research and a glance at the future” (2005) highlights that feed wastage due to overfeeding or improper sizing contributes to water deterioration. Multiple feedings per day,four to five for early stages, two to three for later stages,improve consumption and reduce competition. Slightly less feed should be offered earlier in the day to account for a nocturnal feeding peak. Grading prawns by size before introducing them to the production pond minimises hierarchical feeding behaviour and enhances uniformity. The integration of biofloc technology, as described in “Use of biofloc technology in shrimp aquaculture: a comprehensive review, with emphasis on the last decade” (2021), can reduce reliance on external feed by promoting carbon,to,nitrogen ratios that stimulate heterotrophic bacterial growth. However, biofloc systems require rigorous aeration and regular monitoring of total suspended solids (above 200 mg/L is typical), and they are not suitable for all farms. Professional advice is needed before adopting this system. Production,stage decisions encompass stocking density, size grading, and harvest preparation. Stocking densities for semi,intensive culture usually range from 20 to 60 post,larvae per square metre, depending on aeration capacity and management intensity. Lower densities promote larger individuals, while higher densities increase overall yield but raise the risk of stress and disease. The [USDA APHIS Livestock and Poultry Disease](https://www.aphis.usda.gov/livestock-poultry-disease) and the [USDA National Animal Health Monitoring System](https://www.aphis.usda.gov/livestock-poultry-disease/nahms) provide frameworks for disease surveillance that can be adapted to aquaculture. Size grading should be performed every two to three weeks during the nursery phase and once after the first month in the grow,out pond. This practice reduces size disparity and cannibalism. Harvest preparation involves gradually lowering water temperature over 24 to 48 hours to slow metabolism and reduce stress, followed by purging in clean water for 12 to 24 hours to clear gut contents. Humane harvest methods must be employed, and the [Merck Veterinary Manual](https://www.merckvetmanual.com/) describes cold,water stunning or electrical stunning as acceptable approaches for crustaceans. Workers should be trained in these methods to comply with evolving animal welfare standards. Record,keeping is essential for traceability and management evaluation. At minimum, records should include daily feed amount, number of mortalities, body weight at grading, water quality parameters, and any treatment or disease events. These data allow calculation of [feed conversion ratio](/knowledge/animal-farming/poultry/feed-conversion-ratio-measuring-improving-poultry-efficiency), survival rate, and specific growth rate. Regular comparison against benchmarks,such as those published in “Status of freshwater prawn farming: a review” (1995),helps identify underperformance. Veterinary involvement is indicated when mortality exceeds 5 % in a week or when clinical signs such as melanised lesions, lethargy, or erratic swimming appear. Escalation to a diagnostic laboratory is necessary for pathogen identification. Worker and [food safety](/knowledge/bacteria/livestock-bacteria/cooking-chicken-bacteria-prevention) are inseparable from production management. Personal protective equipment, including gloves and boots, should be used when handling feed additives, disinfectants, or antibiotics. Withdrawal periods for any therapeutant must be observed to avoid residues. The [FAO Animal Production and Health](https://www.fao.org/animal-production/en/) guidance encourages biosecurity protocols such as footbaths, restricted access to ponds, and equipment disinfection between batches. [Food safety](/knowledge/bacteria/livestock-bacteria/cooking-chicken-bacteria-prevention) hazards include bacterial contamination and chemical residues, processors should test for pathogens and maintain cold chains during transport. Failure patterns in freshwater prawn farming often stem from inadequate shelter, poor water quality, or disease outbreaks. Water quality flare,ups are commonly linked to overfeeding or insufficient aeration, leading to hypoxia and ammonia spikes. Disease agents include viruses such as [white spot syndrome virus](/knowledge/viruses/aquatic-viruses/white-spot-syndrome-virus) and bacteria such as *Aeromonas* species. The [PubMed record 42429872](https://pubmed.ncbi.nlm.nih.gov/42429872/) and other review references in the packet underscore the importance of biosecurity and diagnostic capacity. Growers must not attempt to treat diseases without a confirmed diagnosis and a veterinary prescription. Practical monitoring encompasses both environmental and biological indicators. Daily visual checks of prawn behaviour, feeding response, and mortality are supplemented by weekly growth sampling. Automated sensors for dissolved oxygen and temperature can alert managers to acute deteriorations. When uncertainty arises about water chemistry interpretation or disease identification, farmers should contact an aquaculture veterinarian or a regional extension specialist. Professional escalation ensures that decisions are based on evidence instead of anecdote, reducing the likelihood of catastrophic losses. In summary, successful freshwater prawn farming relies on a tightly integrated system of shelter provision, water quality control, graded feeding, and meticulous record,keeping. Each decision,from pond layout to harvest protocol,affects survival, growth, and market quality. Adherence to established guidance from organisations such as the FAO, WOAH, and USDA, combined with professional veterinary collaboration, minimises risks and supports sustainable production. ## Health Observation Daily surveillance of prawn behavior, feed intake, and visible signs of disease is essential. Producers should inspect ponds at dawn and dusk when prawns are most active. Abnormal signs include lethargy, erratic swimming, discoloration of the exoskeleton, red or black spots, fouling of the gills, and reduced feeding response. The presence of dead or moribund prawns at the pond edge or bottom requires immediate investigation. Routine sampling using cast nets or traps can provide a representative health assessment without causing undue stress. Records of daily mortality, feeding behaviour, and water quality parameters (dissolved oxygen, pH, temperature, ammonia, nitrite) should be maintained for each pond to identify trends or deviations. Regular health checks following guidance from [WOAH Aquatic Animal Health Code](https://www.woah.org/en/what-we-do/standards/codes-and-manuals/terrestrial-code-online-access/) help standardize observation protocols. ## Biosecurity Biosecurity measures aim to prevent introduction and spread of pathogens. Farm entry should be restricted to essential personnel and vehicles. Disinfectant footbaths and vehicle tire dips at the farm gate are recommended. Equipment such as nets, buckets, and aerators should be dedicated to individual ponds or disinfected between uses. Source water for ponds should be filtered or treated to exclude wild crustaceans that may carry diseases. New stock should originate from hatcheries certified free of specific pathogens under programmes consistent with recommendations from the [FAO Animal Production and Health](https://www.fao.org/animal-production/en/) division. Any introduction of prawns from external sources should be quarantined in separate tanks or ponds for at least two weeks while observing for clinical signs. Mortality of unknown cause should not be discarded onto the farm perimeter, instead, carcasses should be buried or incinerated to reduce transmission risk. The principles outlined in the [USDA APHIS Livestock and Poultry Disease](https://www.aphis.usda.gov/livestock-poultry-disease) guidance for aquatic species can be adapted to freshwater prawn operations. ## Diagnostic and Veterinary Escalation When abnormal mortality or clinical signs exceed baseline expectations, the producer should contact a veterinarian with experience in aquatic animal health. Diagnostic investigation typically begins with a thorough on-farm assessment of water quality, feeding history, and recent stock movements. Live, moribund prawns are preferred for sampling because they provide the best diagnostic material. The veterinarian may recommend collection of hemolymph, tissue from the hepatopancreas, gills, and muscle, or whole prawns preserved in appropriate fixatives for histopathology, microbiology, or molecular testing. [Polymerase chain reaction](/knowledge/molecular-biology/polymerase-chain-reaction) (PCR) assays are available for several important pathogens of *Macrobrachium rosenbergii* and other freshwater prawns, for example [white spot syndrome virus](/knowledge/viruses/aquatic-viruses/white-spot-syndrome-virus) and *Vibrio* species. Diagnostic interpretation should follow validated procedures such as those described in the [Merck Veterinary Manual](https://www.merckvetmanual.com/). The role of the veterinarian extends to prescribing treatments, which may include bath or medicated feed applications, but only after confirming the etiology. Empirical treatment without diagnosis is discouraged because it can promote antimicrobial resistance and obscure the underlying cause. ## Uncertainty Several aspects of freshwater prawn health management remain poorly understood. The epidemiology of many pathogens in tropical pond environments is not fully characterized, and diagnostic test performance for some agents has not been rigorously validated in the field. Probiotics and immunostimulants are available commercially but their efficacy varies with farm conditions and stocking densities, as noted in recent aquaculture reviews such as [Use of biofloc technology in shrimp aquaculture: a comprehensive review](https://api.elsevier.com/content/abstract/scopus_id/85090473038). The role of environmental stressors,especially low dissolved oxygen and elevated ammonia,in precipitating disease outbreaks is recognized but the quantitative thresholds that trigger clinical disease are not fixed across different production systems. Producers should therefore regard any current guidance as indicative instead of prescriptive and should work with their local aquatic veterinary service to develop site-specific health plans. When in doubt, escalation to regional diagnostic laboratories or academic extension services is appropriate. The [USDA National Animal Health Monitoring System](https://www.aphis.usda.gov/livestock-poultry-disease/nahms) provides surveillance frameworks that can be adapted to aquaculture species. ## Sustainability Sustainable freshwater prawn farming integrates health management with environmental stewardship. Reducing reliance on wild-caught broodstock by using domesticated lines from hatcheries lowers the risk of introducing pathogens and conserves wild genetic resources. Nutrient management, including accurate feed formulation and feeding schedules, minimizes waste accumulation and reduces the biological oxygen demand on receiving waters. The adoption of biofloc or recirculating aquaculture systems can improve water use efficiency and reduce effluent volume, although initial capital costs are higher. Disease outbreaks are a major cause of economic loss and can lead to premature harvests that disrupt local markets. Maintaining high health status through biosecurity and regular monitoring contributes directly to the long-term viability of individual farms and the sector as a whole. International collaboration through organisations such as the FAO and WOAH continues to update standards for sustainable aquaculture practices. ## Frequently Asked Questions **1. How can I distinguish between a water quality problem and an infectious disease?** Changes in dissolved oxygen or ammonia typically affect all individuals in a pond simultaneously, whereas infectious diseases often show a gradual increase in morbidity and may affect specific age classes. Confirm with water testing and diagnostic sampling. **2. What is the most common disease in freshwater prawn farming?** Bacterial infections, particularly those caused by *Vibrio* and *Aeromonas* species, are frequently reported. Fungal and viral agents such as white spot syndrome virus also occur but with less consistency across farms. **3. Should I treat a pond with antibiotics as soon as I see mortality?** No. Antimicrobial treatment should only follow identification of a bacterial pathogen and sensitivity testing. Indiscriminate use promotes resistance and may not improve survival if the cause is viral or environmental. **4. Can I reuse pond water between crops without treatment to save costs?** Reusing untreated water increases cumulative pathogen loads and nutrient levels. Ideally, ponds should be dried and limed between cycles, and incoming water should be filtered. **5. How often should I check water quality parameters in a grow-out pond?** Dissolved oxygen and temperature should be measured at least twice daily. pH, ammonia, and nitrite should be recorded every three to seven days, more frequently during periods of high feeding or stress. **6. What role do wild birds and other animals play in disease spread?** Birds feeding on dead or dying prawns can transport pathogens to other water bodies. Exclusion netting and discouraging loitering birds are proactive biosecurity measures. **7. Is it necessary to have a written health management plan?** Yes. A farm-specific plan that outlines observation protocols, biosecurity measures, response thresholds, and contact information for veterinary services improves consistency and preparedness. **8. Can probiotics replace vaccination or medication in prawn farming?** Probiotics support gut health and water quality but do not substitute for specific disease prevention strategies. No validated vaccines are currently available for freshwater prawns, so probiotics are best used as a complementary tool. ## Educational Veterinary Notice This reference summary provides general guidance on health observation, biosecurity, diagnostics, and sustainability in freshwater prawn farming. It does not substitute for professional veterinary advice tailored to a specific farm. Disease outbreaks can escalate rapidly, producers should establish a working relationship with a licensed aquatic veterinarian before problems arise. Always follow national regulations regarding the use of veterinary medicines and movement of live aquatic animals. Information from [PubMed aquaculture studies](https://pubmed.ncbi.nlm.nih.gov/42295373/) and the [FAO](https://www.fao.org/animal-production/en/) continues to evolve, and readers are encouraged to consult current sources. ## Related Farming Guides - [Aquaculture Water Quality Monitoring](/knowledge/animal-farming/aquaculture/aquaculture-water-quality-monitoring) - [Fish Health Observation And Mortality Investigation](/knowledge/animal-farming/aquaculture/fish-health-observation-and-mortality-investigation) - [Biosecurity For Fish Farms](/knowledge/animal-farming/aquaculture/biosecurity-for-fish-farms) - [Feeding Farmed Fish Efficiently](/knowledge/animal-farming/aquaculture/feeding-farmed-fish-efficiently) - [Recirculating Aquaculture System Basics](/knowledge/animal-farming/aquaculture/recirculating-aquaculture-system-basics) ## Related Clinical & Scientific Guides * [Pond Sediment Management and Dredging Options](/knowledge/animal-farming/aquaculture/pond-sediment-management-dredging-options) * [Indoor Aquaculture Facilities: Lighting and Insulation](/knowledge/animal-farming/aquaculture/indoor-aquaculture-facilities-lighting-insulation) * [Greenhouse Aquaculture: Extending Growing Seasons](/knowledge/animal-farming/aquaculture/greenhouse-aquaculture-extending-growing-seasons) ## References and Further Reading - [FAO Animal Production and Health](https://www.fao.org/animal-production/en/) - [WOAH Terrestrial Animal Health Code](https://www.woah.org/en/what-we-do/standards/codes-and-manuals/terrestrial-code-online-access/) - [USDA APHIS Livestock and Poultry Disease](https://www.aphis.usda.gov/livestock-poultry-disease) - [Merck Veterinary Manual](https://www.merckvetmanual.com/) - [USDA National Animal Health Monitoring System](https://www.aphis.usda.gov/livestock-poultry-disease/nahms) > This article is educational and is not a substitute for veterinary diagnosis, treatment, public-health guidance, or regulatory reporting.