Giant freshwater prawn
Macrobrachium rosenbergii
Also known asMacrobrachium · Scampi (regional)
Water parameters
Minimum tank: 300 L per individual at harvest size.
Feed and growth
- Feed protein
- 35% target
- Daily feed (warm)
- 2.50% of body weight
- Daily feed (cool)
- 0.80% of body weight
- Max density
- 15 g per litre
A 150 g adult eats about 3.8 g of feed per day at optimum. 10 fish at adult size: ~38 g daily.
Legality
Rules vary by jurisdiction and change over time. Verify with your local fisheries or wildlife authority before stocking.
| Jurisdiction | Status | Notes |
|---|---|---|
| California | permit required | Aquaculture permit required verified 2026-05-13 |
| New South Wales | prohibited | verified 2026-05-13 |
Unlisted jurisdictions default to "check local regulations".
Origin and habitat
The giant freshwater prawn (Macrobrachium rosenbergii) is native to rivers and estuaries across Southeast Asia, from India through Malaysia, Thailand, and Indonesia to northern Australia. Larvae develop in brackish water (12-15 ppt salinity); juveniles and adults live in freshwater. The species reaches 25–30 cm body length and 200–500 g in culture, making it the largest commonly farmed freshwater crustacean. It's the basis of a significant aquaculture industry across tropical Asia, with major production in Thailand, India, Bangladesh, China, and Vietnam. Unlike marine shrimp (Penaeus spp.), freshwater prawns can be grown entirely in freshwater systems after the larval stage, making them compatible with aquaponics. The flesh is firm and sweet, comparable to marine prawns, and commands good prices in Asian and specialty Western markets.
Climate and outdoor ponds
- Climate
- tropical (needs warm water year-round)
- USDA zones
- 10–13 (winter low around -1°C or warmer)
- Heating needed
- yes
- Cooling needed
- no
Care notes
An advanced aquaponics addition that provides both nutrient input (prawn waste feeds plants) and a high-value harvest product. Prawns are grown at 26–32°C in the same water as fish; tilapia + prawn polyculture is a well-established practice in Asian aquaculture. They're bottom-dwellers that eat detritus, uneaten fish feed, and supplemental prawn pellet (30-35% protein). Growth to market size (50–100 g) takes 6-9 months from post-larval stage. The main management challenge is that prawns are territorial and cannibalistic, especially during molting when the soft-shelled individual is vulnerable. Dense substrate structure in the tank (bundles of nylon mesh, sections of PVC pipe, or netting hung vertically) provides hiding spots during molting and reduces aggression losses. Stocking density is calculated by bottom area, not volume: 5-15 prawns per square meter of tank bottom. The larvae require brackish water for 30-45 days of development through about 11 larval stages before they metamorphose into post-larvae that can survive in freshwater. This means you either need a separate brackish larval rearing setup or you buy post-larvae (PLs) from a hatchery. Most home aquaponics keepers buy juvenile prawns. Legal status is generally permissive; M. rosenbergii is approved for aquaculture in most US states. Market value is high ($15-30/kg), so even a small harvest from a polyculture system provides meaningful return.