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ShrimphardFreshwater

Giant River Prawn

Macrobrachium rosenbergii

📍 Southeast Asia (Thailand, Malaysia, Indonesia) - wild-caught and commercially farmed

Ask Finn

The Giant River Prawn is a large, robust freshwater shrimp prized for its impressive size and hardy nature. Adults display a translucent to brownish coloration with distinctive long claws and antennae, making them visually striking in larger aquariums. These prawns are significantly larger than ornamental shrimp varieties and require substantial space and specialized care.

Size8"
Min Tank55g
peaceful
Zonebottom

Care Guide

Diet

Giant River Prawns are omnivorous detritivores that graze on biofilm, algae, and decaying plant matter. Supplement with high-quality sinking pellets (Hikari, Fluval Bug Bites), blanched vegetables (zucchini, spinach, carrot), and occasional protein sources like bloodworms or small crustaceans. Feed sparingly 2-3 times weekly, removing uneaten food within 24 hours.

Behavior

These prawns are primarily nocturnal and spend daylight hours hiding in caves, driftwood, or dense vegetation. They are solitary or territorial and will fight with other adult prawns; housing multiple individuals requires very large tanks with abundant shelter. Molting occurs every 4-8 weeks and leaves them vulnerable; provide hiding spots during this period.

Breeding

Giant River Prawns require brackish or saltwater conditions for larval development, making successful breeding in freshwater aquariums extremely difficult or impossible. Females produce large clutches of eggs (500-10,000) but larvae are planktonic and require marine rearing. Most aquarium specimens are wild-caught or farm-raised juveniles.

Common Diseases

Molting Failure / Incomplete Ecdysis

Symptoms

Prawn unable to shed exoskeleton completely; stuck in old shell; lethargy; loss of appetite

Treatment

Ensure adequate calcium and mineral content via GH booster or mineral supplements; maintain stable water parameters; provide soft substrate and hiding spots; increase humidity by misting; may require manual assistance in severe cases

Bacterial Infection / Shell Disease

Symptoms

Soft spots on exoskeleton; discoloration; lesions; cloudy appearance; lethargy

Treatment

Perform 30-50% water change; improve water quality and reduce ammonia/nitrite; add Indian almond leaves or tannins for antibacterial properties; isolate if severely infected; avoid copper-based treatments

Copper Toxicity

Symptoms

Lethargy; loss of appetite; discoloration; neurological symptoms; death

Treatment

Perform immediate large water change (50-75%); use copper-free medications and fertilizers; test water for copper; use RO water if tap water is contaminated; activated carbon may help remove residual copper

Parasitic Infection (Vorticella / Epistylis)

Symptoms

White fuzzy coating on body and appendages; lethargy; difficulty molting; reduced feeding

Treatment

Improve water quality and increase aeration; perform daily 25% water changes; add salt (1-2 tsp per 10 gallons) temporarily; increase temperature slightly to 26-28 C; use formalin-based treatments cautiously (copper-free); provide tannins via botanicals

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Quick Facts

diet
omnivore - detritus, algae, biofilm, plant matter, small invertebrates
lifespan
3-4 years
max size
20 cm (8 in)
tank size
55 gallons minimum for single adult; 75+ gallons recommended
temperament
peaceful but territorial with conspecifics

Water it likes

ph
6.5-8.0
ammonia
0 ppm
nitrate
<20 ppm
hardness
8-15 dGH
temperature
75–82°F (24–28°C)

Stats

Community tips0
Kept by0 hobbyists