Giant Freshwater Prawn - Macrobrachium rosenbergii : Complete Prawn Profile & Care Guide
Table of contents
Introduction
Giant Freshwater Prawns (Macrobrachium rosenbergii) are an intriguing species that can grow to nearly the size of a small lobster, with arms that can reach twice the length of their body. Their large size and active dispositions make them a challenging choice for beginner aquarists. Medium to large-sized Freshwater Prawns exhibit predatory behaviours, which makes selecting suitable tankmates a tricky prospect. For the most part, a species-only tank is the safest option.
If you do decide to add tankmates, they must be large enough to avoid being preyed upon by the Giant Freshwater Prawns, yet not big enough to consume the prawns themselves. A well-armoured, herbivorous fish, such as a larger plecostomus, might be a better choice. Keeping fish of equal size to the prawns is generally not advisable unless you're working with a very small species.
Giant Freshwater prawns demonstrate adaptability to diverse aquatic environments, encompassing both freshwater and slightly brackish conditions. This adaptability hinges on several key factors, including adequate oxygenation and the maintenance of water temperatures within an appropriate range.
The Giant Freshwater Prawns are typically brownish in colour, but this can vary. Smaller individuals may present greenish colouration and faint vertical stripes. The rostrum is very noticeable, containing 8 to 11 ventral teeth and 11 to 14 dorsal teeth. The first pair of pereiopods are elongated and very thin, ending in delicate claws that serve as feeding appendages.
The second pair of pereiopods are much larger and more powerful, particularly in males. The adjustable claws of the second pair are distinctively covered in dense bristles, giving them a velvety appearance. The colour of the claws in males varies according to their social dominance, with blue being the typical colour. The unique physical features of these fascinating creatures make them a popular subject of interest for aquatic enthusiasts and researchers alike.
Giant Freshwater Prawn Photos
Sexual Dimorphism
Distinguishing male from female Giant Freshwater Prawns is relatively straightforward. Typically, females exhibit broader abdomens and smaller second pereiopods than males, while males possess more potent and extensive pereiopods than females.
Quick Facts
| Scientific Name | Macrobrachium rosenbergii |
|---|---|
| Year Described | 1879 |
| Other Names | Giant River Prawn, Malaysian Prawn, Freshwater Scampi, Cherabin |
| Kingdom | Animalia |
| Classification | Malacostraca |
| Order | Decapoda |
| Family | Palaemonidae |
| Genus | Macrobrachium |
| Origins | |
| Max Size | 30 cm |
| Temperament | Semi-Aggressive |
| Aquarium Level | Bottom - Middle |
| Difficulty | Intermediate - Advanced |
| Shoaling | No |
| Best kept as | Trios |
| Diet & Feeding | Omnivore |
| Reproduction | Egg Depositor |
| Average Lifespan | Up to 3 Years |
Water Parameters
| Water Type | Freshwater |
|---|---|
| pH | 7.0 - 8.0 |
| GH | 2 - 9 |
| ℉ | 59 - 86 |
|---|---|
| ℃ | 15 - 30 |
Natural Habitat
The Giant Freshwater Prawn is a fascinating species that can be found throughout subtropical and tropical areas, spanning Southeast Asia, India, and Northern Australia. These prawns have also been introduced to various regions, including parts of China, Thailand, Africa, New Zealand, Japan, the Americas, and the Caribbean. With its impressive size, the Giant Freshwater Prawn is among the largest freshwater prawns globally and is widely farmed in several countries for its culinary value.
These Prawns inhabit rivers, ponds, lakes, and streams across every continent except Antarctica and Europe. Most species are amphidromous, meaning they require both freshwater and brackish water to complete their lifecycles, making them highly adaptable to different environments. These fascinating creatures ' wide distribution and unique lifecycle make them a popular subject of interest for aquatic enthusiasts and researchers alike.
Breeding
Breeding Giant Freshwater Prawns in captivity is a significant challenge due to the complex and specific conditions required. Achieving success requires a dedicated, scientific approach that involves a considerable amount of hard work and yields limited results.
During mating, the male deposits spermatophores onto the female's thorax's underside, between the pereiopods. The female then expels eggs, which pass through the spermatophores. The female carries these fertilized eggs until they hatch, a process that typically takes less than three weeks. Females can lay up to 50,000 eggs up to five times per year.
The eggs hatch into zoeae, representing crustaceans ' first larval stage. Subsequently, they undergo several larval stages before finally metamorphosing into postlarvae, at which stage they resemble the adults. This metamorphosis typically occurs around 32 to 35 days after hatching. The postlarvae then migrate back into freshwater to continue their development.
Diet & Feeding
Compared to other algae-eating and filter-feeding Shrimp that are prevalent in the hobby today, the Giant Freshwater Prawns exhibit omnivorous tendencies. Thus, their dietary requirements extend beyond algae and filter-feeding to include a varied assortment of high-quality dried foods such as granules, sinking pellets, and wafers, as well as meaty foods like earthworms, bloodworms, and brine shrimp. These dietary requirements are essential to ensure the prawns ' optimal growth, development, and overall well-being.
