Giant freshwater prawn
Macrobrachium rosenbergii
Also known asMacrobrachium · Scampi (regional) · Galda chingri
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 the tropical and subtropical Indo-Pacific, from India through Southeast Asia to New Guinea and northern Australia, east of Huxley's Line. It is the largest member of its genus and the largest freshwater crustacean in common culture: males reach about 32 cm and 250 g, females smaller at around 25 cm and 100 to 120 g. Its life cycle straddles salinities. Larvae must develop in brackish water of roughly 10 to 13 ppt, passing through about eleven stages over some 26 to 35 days before they metamorphose into post-larvae that move into fresh water, where juveniles and adults live out their lives. That freshwater adult phase is what makes the prawn, unlike marine Penaeus shrimp, a fit for aquaponics. It anchors a sizable tropical-Asian farming industry, with global output around 300,000 tonnes a year, led by China, India, Thailand, Bangladesh, and Vietnam. The flesh is firm and sweet, much like marine prawns, and sells well 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 add-on that both feeds plants with its waste and yields a high-value crop. Prawns grow at 26–32°C, sharing water with fish; prawn-and-tilapia polyculture is long established in Asian farming. They are bottom-dwellers that scavenge detritus, leftover fish feed, and a supplemental prawn pellet of about 30 to 35 percent protein, reaching a market size of 50–100 g in roughly six to nine months from post-larvae. The chief problem is cannibalism: a freshly molted, soft-shelled prawn is easy prey, and losses climb without cover. Plenty of structure helps, and research shows the prawns strongly prefer vertical or steeply sloped surfaces to molt on, so hanging mesh, netting, and angled pipe work better than flat shelter. Stocking is figured by bottom area rather than volume, on the order of a few to fifteen prawns per square metre, with lower densities giving bigger animals. The catch for hobbyists is the larval stage: larvae need brackish water for about a month through their many stages, so you either run a separate brackish hatchery or, more practically, buy post-larvae or juveniles from a hatchery. Legal status is generally permissive, with M. rosenbergii approved for aquaculture in most US states, and at $15 to $30 per kilogram even a modest polyculture harvest pays off.