Detailed Explanation of Key Points for Polyculture Techniques of Rice Field Eels and Loaches

Polyculture of rice field eels and loaches - that's right, both rice field eels and loaches are something we often see, they can be polycultured together, and polyculture can produce greater benefits and higher yields. Below we discuss the polyculture techniques for rice field eels and loaches.

Polyculture Techniques for Rice Field Eels and Loaches

1. Build a good breeding pond for polyculturing rice field eels and loaches

Choose a location that is sheltered from wind and faces the sun, has a quiet environment and convenient water sources. Cement ponds or earthen ponds can both be used, and net cages can also be set up for polyculture in reservoirs, weirs and ponds, small ditches and small rivers. The area is generally 25-150 sq m.

If cement ponds are used to raise rice field eels and loaches, dealkalization treatment must be carried out before releasing the fry; if earthen ponds are used, the soil is required to be hard and the pond bottom must be tamped solid. The pond depth is 0.8-1.5 m. Whether a cement pond or an earthen pond, a 30 cm layer of fertile mud must be filled into the pond bottom. Fertile mud with more organic matter is best, as this helps rice field eels and loaches dig caves to live in. When building the pond, water inlets and outlets must also be set up, and the water depth should be kept at 15-20 cm. The water inlets and outlets must be secured with fish-blocking nets to prevent rice field eels and loaches from escaping.

About 10 days before releasing the fry, use quicklime to thoroughly disinfect the breeding pond, and 3-4 days before releasing the fry, drain the pond water and then inject fresh water.

Choose polyethylene netting with fine mesh to make net cages. The mesh size should be based on the principle of not letting eels or loaches escape and facilitating water exchange inside and outside the net cage. The area of a single cage should not exceed 20 sq m, and the specifications are generally 5 m-7 m long, 2 m-3 m wide, and 1.5 m-2 m high.

The net cages are fixed along the pond edge with bamboo poles, with the cage opening 0.5 m-0.6 m above the water surface, and a distance of 1.5 m between cages. The total area of net cages should not exceed 10% of the pond area. 7 days-10 days before stocking the fry, soak the new net cages in water so that a layer of algal biofilm attaches to the surface of the netting, to avoid scratching the eels' bodies. Put soil that has been sun-dried or disinfected into the net cage, about 0.2 m thick, so that eels and loaches can burrow into the soil to overwinter in winter. Transplant water peanut into the cage, with the coverage accounting for 70%-80% of the net cage area.

2. Select good rice field eel and loach seedlings and stock them reasonably

Whether breeding rice field eels and loaches succeeds or not, the seedlings are the key. For rice field eel seedlings, it is best to use artificially bred and domesticated dark yellow large-spotted rice field eels or golden yellow small-spotted rice field eels. Mixed-color eel seedlings and non-domesticated eel seedlings cannot be used. The size of rice field eel seedlings is preferably 50-80 tails per kg. If too small, their feeding is poor and the survival rate is also low. The stocking density is generally preferably 1-1.5 kg of eel seedlings per sq m. After the rice field eels have been stocked for 20 days, release loach seedlings at a ratio of 1:10. For loaches, it is best to use artificially bred ones, which have a high survival rate.

Before stocking eel and loach seedlings in the pond, stock seedlings according to conventional breeding requirements. Eel and loach seedlings can be stocked from April to November. The specification for eel seedlings is about 20 g/tail. Rice field eels in the same net cage should be as uniform in size as possible to avoid eating each other.

Stock as early as possible to help improve the out-of-cage specification. For each sq m of net cage, stock 2 kg of rice field eels with a specification of 25 g and 0.5 kg of loaches; or stock 3-4 kg of rice field eels with a specification of 50 g and 1 kg of loaches. 3-5 days before stocking the seedlings, disinfect the water peanut and the water body with bleaching powder aqueous solution. For disinfecting eel and loach seedlings, soak in 10 ppm methylene blue aqueous solution for 10-15 [minutes], or bathe in 20 ppm potassium permanganate aqueous solution for 5-10 minutes, or soak in 3%-4% salt water solution for 3-5 minutes.

3. Feed compound feed

First install feeding trays. The feeding trays can be made of wooden boards or plastic boards, and the area can be determined by the size of the pond, 5 cm below the water surface. Do not feed during the first 3 days after releasing rice field eel seedlings, so the rice field eels can adapt to the environment. Start feeding from the fourth day. Feeding at around 7 p.m. every day is best, as the rice field eels' feed intake is highest at this time. For artificial breeding of rice field eels, compound feed is the main feed, with appropriate feeding of some live feeds such as small fish, small shrimp, earthworms, fly maggots, river snails, yellow mealworms, silkworm pupae, pig blood and animal offal.

For artificially domesticated rice field eels, compound feed and earthworms are their favorite feeds. Using artificially bred dark yellow large-spotted rice field eel seedlings and feeding compound feed, the daily feeding amount is 3%-5% of the rice field eel body weight, fed 1-2 times per day (depending on weather and water temperature), using the principle of fixed timing and fixed quantity. Rice field eel seedlings raised at 20 g can grow to 200-300 g in one year.

Loaches in the pond mainly feed on the feces excreted by rice field eels and the uneaten rice field eel feed. Part of their food can also be solved by fertilizing the water quality. Loaches reproduce naturally and quickly. When the proportion of loaches in the pond is greater than 1:10, feeding bran once a day is enough. The feeding amount should be small at the beginning and then gradually increased.

When artificially breeding rice field eels, it is best to release a certain proportion of loaches after the feeding-training work is finished, so as to achieve mutually beneficial symbiosis between rice field eels and loaches and create good economic benefits. This is because loaches and rice field eels have different feeding habits and different acceptance of compound feed.

Loaches can adapt almost without feeding training, while rice field eels need a period of somewhat forced feeding training to adapt. During feeding training, it is often the case that before the rice field eels have started eating, the loaches have already eaten it all clean, thus affecting the feeding-training time of the rice field eels, and even causing the feeding training to fail. Loaches are active and dart up and down when feeding, causing large water fluctuations, so that part of the feed is lost into the water, polluting the water quality and affecting the utilization rate of the compound feed, thereby prolonging the feeding-training time.

4. Feeding management

The growing season for rice field eels and loaches is April-November, of which the peak season is May-September. During this period, management should be done with "diligence" and "carefulness", that is, frequent pond patrols and frequent management, and timely solving of problems when found. Persist in checking the cages morning and evening, prevent escape, prevent rats, prevent theft, prevent flooding, and promptly remove water peanut that grows too vigorously in the cage to prevent it from growing outside the cage and causing eels and loaches to escape. After November, if no soil layer has been set in the cage, the water peanut can be thickened to 0.3 m, then pressed down with heavy objects, letting the eels and loaches hide among it to overwinter.

Carefully observe the growth status of rice field eels and loaches in the pond so as to promptly adopt corresponding measures. The habit of rice field eels and loaches is to hide by day and come out at night. Keep the pond water fresh and clear, with a pH value between 6.5-7.5, and a suitable water level.

5. Prevention is the main approach for eel diseases

Frequently splash the whole pond with 1-2 ppm bleaching powder, and regularly use copper sulfate medicine to prevent diseases. Because once rice field eels become sick, the treatment effect is relatively poor, so prevention is more important than treatment.

Raising loaches together with rice field eels in the breeding pond is helpful to the rice field eels. Loaches like to dart up and down and will also eat debris in the water body, which can purify water quality and increase oxygen. Many people say rice field eels will not get sick. Prevent disease before it occurs. Friends who want to raise loaches and rice field eels can try raising them together.