Detailed Explanation of High-Density Grass Carp Farming Techniques

AbstractSelecting flowing water for farming grass carp can shorten their growth cycle and increase yield. The farming pond is best built in a circular, fan-shaped or oval shape, and should be constructed in a location with abundant water sources, clear water quality and suitable water temperature, such as around a pollution-free water system with a continuous mountain spring flow or near a power plant where waste hot water flow can be utilized. Build the relevant facilities inside the pond, select larger-sized fry for stocking, and carry out disease prevention and daily management properly.

Carrying out high-density intensive farming of grass carp in a manually controlled water body can shorten their growth cycle, accelerate growth speed, and increase yield and economic returns.

Generally, flowing water fish farming yields about 40% more than conventional fish farming. Since China is rich in water resources such as reservoirs, rivers and mountain streams, it is convenient to carry out flowing water fish farming; the water flowing out of the flowing water fish pond can also be used to irrigate farmland, saving water resources to a certain extent. It has good development prospects and is a new farming technique currently being vigorously promoted in China.

1. Site Selection for Flowing Water Fish Farming

It is best to choose a location with abundant water sources, clear water quality, stable water level, and a water temperature that can be maintained between 15-30°C from May to October for flowing water fish farming. It requires sufficient sunlight, adequate oxygen content in the water, and convenient transportation for feed and fish fry.

The farming pond is best built in a place with a natural drop that can divert water from reservoirs, irrigation canals or streams by gravity flow, around a pollution-free water system with a continuous mountain spring flow, or near a power plant where waste hot water flow can be utilized. Farming grass carp with flowing water in this way can reduce costs and increase returns to a certain extent.

2. Pond Construction and Area

The pond for flowing water fish farming is best circular, fan-shaped or oval, so that the pond water can circulate without dead corners. The pond walls are built with bricks or stones, with the surface smoothed with cement, the bottom leveled and smoothed with concrete, and the pond ridges built solidly. The inlet and outlet of the pond should be built into slopes to guide the water flow to rush down to the bottom layer and stir the pond water, ensuring water exchange at the pond bottom and smooth discharge of waste.

For ponds where the water source can flow by gravity, the area is best controlled at around 40-100 sq m; if the water source needs to be pumped with power, the area should be controlled at around 20-40 sq m. The waste discharge outlet and drainage outlet in the fish pond should be designed separately, and nets to prevent fish from escaping should be installed at the inlet and outlet, with the mesh size chosen according to the size of the fry.

3. Stocking Fry

Flowing water fish farming facilitates water exchange, increases the oxygen content in the water, and improves the metabolism and digestion and absorption capacity of the fish. Appropriately increasing the stocking density of fish during farming can increase yield.

Before stocking fry, first spread quicklime into the pond at a ratio of 120g/sq m for disinfection. Before the fry are stocked into the pond, soak them in a 3% salt solution for disinfection for 5 minutes. When farming grass carp, 10% common carp or bream can be polycultured in the pond. Select fry of about 150-400g for stocking, and control the density at around 5-10 fish/sq m.

4. Daily Management

When farming fish with flowing water, it is best to choose surface flowing water with higher water temperature and oxygen content from natural water bodies. The fish farming volume should be somewhat larger, but the flow rate must not be too high. If the flow rate is too high, feeding difficulty will increase, and the fish will consume more energy.

When farming grass carp, mainly feed green fodder such as aquatic plants, terrestrial grasses, pumpkin leaves and bean leaves. To meet the nutritional needs for grass carp growth, some concentrated feed and artificial compound feed should also be appropriately added. In the first few days after stocking the fry, the daily feed amount should account for 3% of the total weight of the fish school. As the fry continue to grow, the feeding amount increases to 5-7% of the total weight of the fish school. Generally, feed is given once every 2 hours.

During the farming process, grass carp should be injected with vaccines to prevent diseases. Waste discharge and disinfection of the pond should be carried out once every 2 days, and once a day when the weather is hot. Check the anti-escape facilities around the pond every day, and repair them promptly if damaged. Observe the grass carp more