Grass carp is not just any ordinary fish. It is nature’s own cleaning machine that swims through ponds and eats up unwanted aquatic weeds like hydrilla and vallisneria. Originally from China, grass carp was introduced to Indian fish farming in the 1950s to solve the problem of weed-choked ponds. Since then, it has become an important part of composite fish farming in states like Uttar Pradesh, Bihar, Assam, West Bengal, and Tamil Nadu.
What makes grass carp special is that it does not compete for food with other common carps like Catla, Rohu, or Mrigal. It feeds on plants growing inside the pond, making it both cost-effective and environmentally friendly.
Natural Habitat and Behavior
Grass carp prefer freshwater environments with abundant submerged vegetation. They thrive in warm water with temperatures between 20 to 30 degrees Celsius and can survive in water bodies ranging from rivers to ponds and reservoirs. Unlike other carps, they grow rapidly on a diet of soft aquatic plants and need clean, oxygen-rich water for best performance.
This fish tends to stay close to the edges of the pond where weeds are thick. It has a long, torpedo-shaped body and a silver-green coloration that helps it blend in with its environment. Grass carp are known to grow quickly, reaching up to 1 to 1.5 kilograms within the first year under proper care.
Feeding and Weed Control Benefits
One of the main reasons farmers love grass carp is because it helps control pond weeds naturally. A single fish can consume up to 40 to 70 percent of its body weight in aquatic vegetation every day. This means farmers can reduce or even eliminate the need for chemical or manual weed removal.
In well-managed ponds, grass carp can help maintain a balanced ecosystem. With fewer weeds, there is more space and oxygen for other fish species to thrive. Additionally, cleaner ponds make netting and harvesting easier for the farmer.
Seed Stocking and Composite Culture
Grass carp does not breed naturally in confined ponds in India. Therefore, hatchery-produced fingerlings are used for stocking. Farmers can purchase healthy fingerlings from government or private hatcheries during the start of the culture season.
In composite fish farming, grass carp is typically stocked with Catla, Rohu, Mrigal, and sometimes Silver carp. Since grass carp is a surface-to-mid-level feeder that eats aquatic plants, it does not interfere with other species that consume zooplankton, detritus, or bottom algae.
Stocking density depends on pond size and weed availability. Usually, 500 to 1000 grass carp per hectare are sufficient to control weeds and generate good income when grown along with other species.
Growth Rate and Market Potential
Grass carp is among the fastest-growing carps in India. Under good management, the fish can grow up to 2.5 to 3.5 kilograms within 12 to 14 months. Larger fish can reach 6 to 8 kilograms or more in 2 to 3 years.
There is strong market demand for grass carp due to its white, soft, boneless flesh, especially in Eastern India and Northeastern states. It fetches good prices ranging from Rs. 100 to Rs. 160 per kilogram depending on size and location. Because it grows big and is easy to harvest, many fish farmers see it as a dependable species for boosting income.
Pond Management and Water Quality
To achieve healthy growth, pond water should be regularly monitored. Clear water with plenty of aquatic plants is ideal. If vegetation is scarce, farmers can feed the fish with green fodder like Napier grass, spinach, banana leaves, or even vegetable waste.
Care should be taken not to overstock or overfeed, as this may reduce oxygen levels or lead to poor water quality. Farmers are advised to conduct partial water exchange during summer and avoid using harmful chemicals in weed control when grass carp is being raised.
Support and Training
Grass carp farming is supported by various government fisheries departments, Krishi Vigyan Kendras, and the National Fisheries Development Board (NFDB). Farmers can attend training programs to learn about composite culture, disease management, and improved feeding methods.
Subsidies are also available under the PM Matsya Sampada Yojana and other schemes for fish seed, pond renovation, and feed procurement.
Grass carp is more than just a fish. It is a silent helper that cleans ponds, saves labor, and adds weight to the harvest. For Indian farmers with small ponds or larger water bodies, it presents an eco-friendly, low-maintenance, and profitable solution. With increasing awareness and adoption of scientific fish farming practices, grass carp is emerging as a favorite among rural fish growers aiming for higher productivity and income.
