Can you raise freshwater prawns in aquaponics? Yes, as a warm-season or secondary crop. Freshwater prawn aquaponics uses the giant river prawn, Macrobrachium rosenbergii, which Kentucky State University raises in temperate climates. Keep water above 68°F (20°C), pH 7.0–8.5 and dissolved oxygen of at least 3 ppm, and give these territorial animals plenty of substrate.
Key takeaway: Freshwater prawns are large, sweet-tasting crustaceans that some growers add to an aquaponics system alongside or instead of fish. Kentucky State University (KSU) and the Southern Regional Aquaculture Center (SRAC) have decades of research on raising them in temperate climates, and KSU’s aquaponics manual notes graduate research on using prawns to control solids in raft troughs.
| Factor | Guideline | Source |
|---|---|---|
| Species for freshwater prawn aquaponics | Macrobrachium rosenbergii | Kentucky State University |
| Stocking temperature | Mornings consistently above 68°F (20°C) | SRAC 484 |
| Nursery temperature | 78–82°F (26–28°C) | Kentucky State University |
| pH | 7.0–8.5 | SRAC 484 |
| Dissolved oxygen | At least 3 ppm | SRAC 484 |
| Hardness | 50–200 mg/L | SRAC 484 |
What Prawns Are Used in Freshwater Prawn Aquaponics?
Tropical freshwater crustaceans. KSU says most U.S. culture focuses on the giant Malaysian prawn, Macrobrachium rosenbergii, a native of southern Asia. Young prawns spend about 30 days as larvae in brackish water before moving to fresh water, so home growers buy nursed juveniles rather than breeding them. KSU notes the seedstock process is demanding.
- Species: Macrobrachium rosenbergii.
- Start with: nursed juveniles, about 0.3–0.5 g each.
- Breeding: larvae need brackish water, so leave it to hatcheries.
How Do You Stock Freshwater Prawn Aquaponics?
Acclimate the juveniles slowly. SRAC says to check that the receiving water is close to the temperature of the transport water, and if the difference is greater than 5°F (about 3°C), acclimate the prawns gradually before release. KSU says nursed juveniles are typically held for about 60 days in nursery tanks at 78–82°F (26–28°C) before stocking, so ask your supplier how they were raised.
Can Fish Share Tanks in Freshwater Prawn Aquaponics?
Not in the same open tank as predatory fish. SRAC says prawns should not be stocked in ponds containing fish, except fish confined in floating cages, which keeps the fish from eating the prawns. Many growers therefore keep prawns in a separate tank or in the plant troughs. KSU’s 2021 aquaponics production manual notes graduate research evaluating prawns as biological solids control in the hydroponic troughs of raft systems.
Read our aquaponics raft system guide for the trough setup.
What Water Temperature Does Freshwater Prawn Aquaponics Need?
Warm water. SRAC says to stock prawns only when early-morning water temperatures consistently stay above 68°F (20°C), and KSU keeps nursery tanks at 78–82°F (26–28°C). SRAC advises harvesting when daily water temperatures fall to about 62–68°F (17–20°C) for four or five days, or before a cold front brings lethal temperatures. Indoors, a heater keeps the season going.
- Stock: above 68°F (20°C).
- Nursery: 78–82°F (26–28°C).
- Harvest: before water drops toward the low 60s°F (16–17°C).
Our aquaponics water temperature guide covers heating.
What pH Works for Freshwater Prawn Aquaponics?
Slightly alkaline, hard water. SRAC recommends a pH of 7.0 to 8.5, hardness of 50 to 200 mg/L and total alkalinity of about 100 to 150 mg/L. It notes prawns can survive pH 6.5 to 9.5, but pH above 9.0 is undesirable for stocking. Prawns survive dissolved oxygen below 2 ppm, but SRAC says to keep at least 3 ppm to avoid stress.
SRAC’s aquaponics fact sheet recommends keeping pH close to 7.0 for plant nutrient availability, so aim for the low end of the prawn range, around 7.0–7.5.
Why Does Freshwater Prawn Aquaponics Need Substrate?
They are territorial. SRAC says freshwater prawns are territorial, so as total weight in a pond rises, growth slows; this is called density-dependent growth. Adding substrate turns a flat bottom into three-dimensional space and increases production; SRAC names orange polyethylene safety fencing as a preferred, inexpensive material. In a tank, vertical mesh panels can serve the same purpose.
- Add: vertical mesh, netting or fencing panels.
- Why: more surface means less fighting and better growth.
- Watch: growth slows as total prawn weight rises.
What Do Prawns Eat in Freshwater Prawn Aquaponics?
Sinking pellets. KSU says nursery prawns are fed trout starter feeds at a declining percentage of body weight, and broodstock receive a high-quality marine shrimp diet or sinking salmonid pellet. SRAC discusses formulated feeds for growout. Because prawns feed on the bottom, sinking feed is essential, and leftover feed should be removed before it fouls the water.
How Long Does Freshwater Prawn Aquaponics Take?
About one warm season. SRAC says pond production in temperate climates involves stocking nursed juveniles followed by 3½ to 6 months of growout, with growout often 110 to 170 days. KSU says interest has grown partly because prawns grow faster at cooler temperatures than once thought and because of inland markets for live and fresh prawns.
Does Freshwater Prawn Aquaponics Feed Plants Enough?
Not always on their own. In a 2011 International Journal of Recirculating Aquaculture study, Bakhsh and Chopin grew prawns with lettuce in a prototype recirculating aquaponic system and found prawn growth could be desirable when sufficient macro and micronutrients were supplied, while ammonia and nitrate were critical to water quality. Plan to test and supplement. See our aquaponics nutrient deficiencies guide.
FAQ About Freshwater Prawn Aquaponics
Can freshwater prawns live in aquaponics?
Yes, in warm, well-oxygenated, hard water.
What temperature do freshwater prawns need?
Above 68°F (20°C); nurseries run 78–82°F (26–28°C).
Can prawns live with tilapia?
Only if the fish are caged, per SRAC.
What pH do freshwater prawns need?
About 7.0–8.5.
Can I breed freshwater prawns at home?
It is hard; larvae need brackish water.
How long until harvest?
About 3½ to 6 months of growout.
Sources
- Kentucky State University Aquaculture — Prawn (Shrimp)
- Southern Regional Aquaculture Center — Pond Production of the Freshwater Prawn in Temperate Climates (SRAC 484)
- Kentucky State University — Aquaponics Production Manual: A Practical Handbook for Growers (2021)
- Bakhsh and Chopin, International Journal of Recirculating Aquaculture (2011) — Water Quality and Nutrient Aspects in Recirculating Aquaponic Production of the Freshwater Prawn and Lettuce
- Southern Regional Aquaculture Center — Aquaponics: Integrating Fish and Plant Culture (SRAC 454)
- Photo credits (Wikimedia Commons, edited with titles): Macrobrachium rosenbergii by This illustration was made by Citron You must credit this : Citron / CC-BY-SA-3. (CC BY-SA 3.0); Washington DC Zoo – Macrobrachium rosenbergii 1 by Jarek Tuszyński (CC BY-SA 3.0); Macrobrachium rosenbergii in Gifu World Fresh Water Aquarium – 1 by KKPCW (CC BY-SA 4.0)