Giant river prawn
The largest freshwater prawn in the aquarium trade and one of the most widely farmed animals in the world. Sold small as an oddity, it reaches thirty centimetres with claws longer than its body and will eventually eat most of what it lives with.
Quick profile
- Scientific name
- Macrobrachium rosenbergii
- Adult size
- 25–32 cm (9.8–12.6 in)
- Lifespan
- 2–3 years
- Temperature
- 26–30 °C (79–86 °F)
- pH
- 7–8.5
- Hardness
- 8–20 °dGH
- Minimum tank
- 300 L (79 US gal)
- Minimum length
- 120 cm
- Swimming zone
- Bottom
- Social
- Solitary and territorial
- Diet
- Omnivore
- Overall confidence
- moderate confidence
What keeping this species involves
Not difficult to keep alive and difficult to house honestly. Almost every one sold goes into a tank that will be far too small within a year.
Large lowland rivers and estuaries, with adults well upstream and larvae downstream in brackish water.
Identity and names
- Common name
- Giant river prawn
- Scientific name
- Macrobrachium rosenbergii
- Family
- Palaemonidae
- Order
- Decapoda
- Class
- Malacostraca
- Also sold as
- Macrobrachium rosenbergii, Malaysian prawn, blue lobster prawn, scampi
Adult size and growth
25–32 cm (9.8–12.6 in) — Total length including the extended claws, which are much longer than the body in dominant males.
Typical lifespan in an aquarium: 2–3 years. Almost every animal sold in a shop is a juvenile, so the tank has to suit the size in the first line rather than the size in the bag.
Shape, which is what the compatibility engine reads instead of length alone: elongate with a large — a piscivore's mouth. Macrobrachium rosenbergii is a predator. A 30 cm prawn with 40 cm claws is not a cleanup crew.
Water and tank requirements
An animal reaching thirty centimetres with a leg span wider again, and a strong territorial streak. The floor area is what stops two of them meeting.
Temperature (°C)
Scale: 0 to 36 °C.
pH (pH)
Scale: 4 to 9.5 pH.
Hardness (°dGH)
Scale: 0 to 30 °dGH.
Why these ranges: The band follows the warm lowland rivers it is farmed and collected in. Growth slows markedly below this temperature range, which is a welfare consideration for an animal whose adult size is the point.
Where these figures come from
Habitat class
Brackish and estuarine
Water where fresh meets salt — estuaries, mangrove, tidal creeks and coastal lagoons — with salinity that changes with the tide.
Salinity is a requirement, not a tolerance, for the species genuinely from here — and the commonest way these animals are killed is being sold and kept as freshwater fish.
- Conductivity
- 2000–35000 µS/cm
- Salinity
- 1–20 ppt
- Flow
- variable
- Dissolved oxygen
- moderate
- Seasonality
- moderate
These are figures for the KIND of water body, not measurements of this species. They are AquariumHQ’s summary of the general limnology and are given wide because the water is.
- TemperatureReasoned on this record
- This record states its own reason for this band. See the water section.
- pHReasoned on this record
- This record states its own reason for this band. See the water section.
- General hardnessReasoned on this record
- This record states its own reason for this band. See the water section.
| Requirement | Value | Notes |
|---|---|---|
| Temperature | 26–30 °C (79–86 °F) | Stability matters more than hitting an exact figure. |
| pH | 7–8.5 | A stable pH outside the ideal band is usually better than an unstable one inside it. |
| General hardness | 8–20 °dGH | Check your supplier's published figure before choosing species. |
| Minimum volume | 300 L (79 US gal) | A floor, not a recommendation. |
| Minimum footprint | 120 cm long | An animal reaching thirty centimetres with a leg span wider again, and a strong territorial streak. The floor area is what stops two of them meeting. |
| Water flow | moderate | Match the outflow to this rather than to the filter's rating. |
| Lid required | Yes | This species jumps. |
| Structure | Open sand with caves and wood. Each adult needs a shelter it can occupy alone, particularly around a moult. |
Behaviour
- Males develop enormously elongated blue claws used for display and for holding territory.
- Digs, rearranges and uproots as a matter of routine, so a planted layout does not survive it.
Feeding
Actively predatory as it grows. Anything slow, small or asleep is food, and that includes tankmates it ignored for months.
- Diet type
- Omnivore
- Staples
- Sinking pellets, Frozen fish and shellfish, Blanched vegetables, Cuttlebone
Breeding
- Strategy
- Larvae require brackish water; a commercial hatchery process, not an aquarium one
- Difficulty
- rarely achieved
- Parental care
- carries eggs
Tankmates and compatibility
Assessments are derived from stored traits by the compatibility engine, with the reasoning shown. A verdict is a statement about probability, not a guarantee — individual temperament can override it.
| Towards | Risk | What it means |
|---|---|---|
| Small fish | near-certain | Anything that fits in the mouth is at risk once this species reaches adult size. |
| Adult dwarf shrimp | near-certain | Cover reduces losses but rarely prevents them where the risk is high. |
| Shrimplets | near-certain | Determines whether a shrimp colony can grow rather than merely persist. |
| Snails | high | Applies to snails you wanted as well as snails you did not. |
| Long or trailing fins | none | Fin damage is an entry point for secondary infection. |
| Plants | nibbles | Tough species such as Anubias and Java fern survive most grazers. |
Any pair in the catalogue can be assessed with the compatibility checker.
Welfare considerations
Points where the way this species is commonly sold or kept differs from what it actually needs.
- Sold at four centimetres with no indication of adult size. The mismatch between purchase and requirement is the central welfare problem here.
- Moulting adults are helpless for hours and are killed by their own kind more often than by anything else.
- Escapes readily and can cross damp surfaces. A heavy, closed lid is a requirement rather than a precaution.
Problems to watch for
Most problems in a tank containing this species are general rather than species-specific. Start with the troubleshooting index and work from the observation rather than from a guess at the cause.
What AquariumHQ does not yet hold
Species-level disease susceptibility is modelled in the graph and is not yet populated. Health pages will not be published until each condition has veterinary sourcing, because health content written without evidence is the most harmful thing this product could publish. The gap is recorded in the coverage report.
Where it comes from
- Native range
- Native to the Indo-Pacific; farmed and introduced far beyond it
- Habitat
- Large lowland rivers and estuaries, with adults well upstream and larvae downstream in brackish water.
What the checklists say
91 distribution statements retrieved from GBIF checklists. Establishment means is reproduced from the source where it states one, and left unstated where it does not — a record of presence is not a record of origin.
| Status | Places | What this means |
|---|---|---|
| Introduced | 78 | A checklist states the species arrived here with human help. That is not a statement that it is established, harmful or illegal. |
| Recorded as present, establishment means not stated | 13 | The source records the species as present and does not say whether it is native or introduced. AquariumHQ does not fill that in. |
No checklist AquariumHQ holds positively calls this species native anywhere, so the native range above rests on AquariumHQ’s own reading of the literature rather than on a cited checklist.
Legal status and responsible practice
Restriction note
One of the most widely farmed freshwater animals in the world, which means many countries regulate it as aquaculture stock rather than as an ornamental — a different set of rules, often with import permits attached, and not one AquariumHQ has established for any jurisdiction. Escapees have founded breeding populations on several continents. Ask which regime applies where you are before buying, because the aquaculture one is easy to breach without realising it exists.
Where this species has been introduced, and what followed
Hawaii and the southern United States
Recorded, not establishedProbable escape from aquaculture. NAS notes that in Hawaii the species is extensively cultured in ponds but probably has not become established in streams.
- Escape from food or bait aquacultureFood and bait production, at a scale no private keeper approaches. The animals are held in numbers, in ponds, often on floodplains.
What has been established
- Carries parasites or pathogensReported in the literatureA carrier of, and resistant to, white spot virus, and therefore a possible route for spreading the disease to native shrimp species.USGS Nonindigenous Aquatic Species database credits: Hameed et al. 2000
USGS Nonindigenous Aquatic Species database · Species Profile — Means of Introduction; Species Profile — Impact of Introduction · read 2026-08-29. A United States database: the routes and effects recorded here are the ones documented there, and say nothing about other regions.
Never release aquarium life into the wild
Aquarium animals, plants, and aquarium water must never be released into ponds, rivers, canals, drains or the sea — not even in a country where the species is sold freely. Released fish and invertebrates establish populations that displace native species, and released plants and water carry pathogens, parasites and fragments capable of spreading without any animal at all. If you can no longer keep an animal, rehome it through an aquarium society, a retailer that accepts returns, or another keeper.
- Rehome through a local aquarium society, a specialist retailer or another keeper.
- Unwanted plants go in household waste or a hot compost heap, never in a watercourse or a garden pond.
- Never empty a bucket of tank water into a drain that discharges to open water.
- If an animal is beyond rehoming, ask an aquatic veterinarian about humane euthanasia rather than releasing it.
Legal status is recorded from the sources named and was correct on the verification date shown. Rules change, and sub-national rules often differ from national ones. Check the current position with the relevant authority before acquiring, selling or moving any animal or plant.
Evidence
Every stored value with the kind of support behind it and where to check it. Evidence type and confidence are separate axes: an editorial position held confidently and a measurement held tentatively are different things.
| Claim | Value | Evidence type | Confidence | Source |
|---|---|---|---|---|
| scientific name | Macrobrachium rosenbergii | Observed / measured | high confidence | Catalogue of Life; GBIF — Global Biodiversity Information Facility |
| native range | Native to the Indo-Pacific; farmed and introduced far beyond it | Observed / measured | moderate confidence | GBIF — Global Biodiversity Information Facility |
| adult size | 25–32 cm | Aquarium-literature consensus | moderate confidence | AquariumHQ husbandry synthesis |
| lifespan | 2–3 years | Aquarium-literature consensus | moderate confidence | AquariumHQ husbandry synthesis |
| temperature | 26–30 °C | Aquarium-literature consensus | moderate confidence | AquariumHQ husbandry synthesis |
| ph | 7–8.5 pH | Aquarium-literature consensus | moderate confidence | AquariumHQ husbandry synthesis |
| general hardness | 8–20 °dGH | Aquarium-literature consensus | moderate confidence | AquariumHQ husbandry synthesis |
| minimum tank volume | ≥ 300 L | AquariumHQ editorial position | moderate confidence | AquariumHQ husbandry synthesis |
| minimum tank length | ≥ 120 cm | AquariumHQ editorial position | moderate confidence | AquariumHQ husbandry synthesis |
Last reviewed 2026-08-10. Values labelled as an aquarium-literature consensus are AquariumHQ editorial positions rather than measurements — see how evidence is handled.
Why we say this
What each figure on this page rests on, and how far that is from being independently established.
Every figure on this page has a provenance. Open any claim to see what AquariumHQ holds for it, which sources say what, and what a claim of that kind actually needs. Different claims need different evidence: an accepted scientific name is settled by one authority, while a legal restriction needs a current primary instrument. A single source is often the right answer rather than a thin one.
scientific nameAquariumHQ's own position, externally checkableBased on a verified authoritative source.
AquariumHQ's own position on a claim an external source could support.
What this kind of claim needs: accepted scientific name and classification — 1 authoritative source in an appropriate context. Checked against gbif on 2026-08-13. One authoritative backbone is what this class requires.
What would improve this: Go and read a source. This is reachable and has not been reached.
native rangeAquariumHQ's own position, externally checkableBased on a verified authoritative source.
AquariumHQ's own position on a claim an external source could support.
What this kind of claim needs: where the species occurs — 1 authoritative source in an appropriate context. 91 distribution statements held from GBIF checklists — introduced in 61 country. Establishment means is reproduced from the source, never inferred from occurrence.
What would improve this: Go and read a source. This is reachable and has not been reached.
adult sizeOne sourceAquariumHQ's own position, derived from evidenced inputs.1 citation, 1 independent origin
A single source: FAO 2005-2012.
- 320 mm — USGS Nonindigenous Aquatic Species database · Maximum recorded · Observed in the wild · checked 2026-08-29
What this kind of claim needs: size a well-kept specimen reaches — no external source is required, provided AquariumHQ shows its reasoning. A documented maximum is held and the catalogue's typical adult range is stated separately, with the relationship between them recorded rather than collapsed. The catalogue's typical adult range already reaches the largest recorded specimen.
What would improve this: Corroborate against a second, independent source.
lifespanAquariumHQ's own position, externally checkableAquariumHQ's own position, derived from evidenced inputs.
AquariumHQ's own position on a claim an external source could support.
What this kind of claim needs: what aquariumhq advises for keeping — no external source is required, provided AquariumHQ shows its reasoning. No external source is required for this class. AquariumHQ's position stands on its stated reasoning.
What would improve this: Go and read a source. This is reachable and has not been reached.
temperatureAquariumHQ's own position, externally checkableAquariumHQ's own position, derived from evidenced inputs.
AquariumHQ's own position on a claim an external source could support.
What this kind of claim needs: what aquariumhq advises for keeping — no external source is required, provided AquariumHQ shows its reasoning. No external source is required for this class. AquariumHQ's position stands on its stated reasoning.
What would improve this: Go and read a source. This is reachable and has not been reached.
phAquariumHQ's own position, externally checkableAquariumHQ's own position, derived from evidenced inputs.
AquariumHQ's own position on a claim an external source could support.
What this kind of claim needs: what aquariumhq advises for keeping — no external source is required, provided AquariumHQ shows its reasoning. No external source is required for this class. AquariumHQ's position stands on its stated reasoning.
What would improve this: Go and read a source. This is reachable and has not been reached.
general hardnessAquariumHQ's own position, externally checkableAquariumHQ's own position, derived from evidenced inputs.
AquariumHQ's own position on a claim an external source could support.
What this kind of claim needs: what aquariumhq advises for keeping — no external source is required, provided AquariumHQ shows its reasoning. No external source is required for this class. AquariumHQ's position stands on its stated reasoning.
What would improve this: Go and read a source. This is reachable and has not been reached.
minimum tank volumeAquariumHQ's judgement — no authority publishes thisAquariumHQ's own position, derived from evidenced inputs.
No external authority publishes this. The rationale carries the reasoning.
What this kind of claim needs: minimum tank size — no external source is required, provided AquariumHQ shows its reasoning. No authority publishes this. AquariumHQ derives it, and the derivation is recorded with its inputs and assumptions.
What would improve this: Keep the rationale current. There is no source to find.
minimum tank lengthAquariumHQ's judgement — no authority publishes thisAquariumHQ's own position, derived from evidenced inputs.
No external authority publishes this. The rationale carries the reasoning.
What this kind of claim needs: minimum tank size — no external source is required, provided AquariumHQ shows its reasoning. No authority publishes this. AquariumHQ derives it, and the derivation is recorded with its inputs and assumptions.
What would improve this: Keep the rationale current. There is no source to find.
Guides relevant to this species
Chosen from this record's own traits rather than listed on every page.
- Predator and prey sizeIt takes fish that fit in its mouth, and its mouth grows with it.
- Native, introduced and invasiveThis record carries an invasive or legal note, and those are five separate claims that are easy to read as one.
- Wild conditions and aquarium recommendationsThe water band on this page is an AquariumHQ position with a stated reason, not a measurement of a river.
- How aquarium species get into the wildThis species has a documented introduction outside its native range, with the route recorded.
- Rehoming an animal you can no longer keepThis animal reaches 32 cm. Most of the difficult rehoming cases are fish sold small that were always going to become impossible.
Group size and social behaviour
Dominant males hold territory and kill rivals, most often catching them soft after a moult. One adult per tank is the practical rule.