Why does rice field eel farming fail? Summary of common causes

Rice field eel farming is also one of the special aquaculture operations. When raised properly, the economic returns are higher than those of fish farming, so in rural aquaculture, the number of households raising rice field eels has been expanding continuously in recent years. However, among the farmers raising rice field eels, quite a few have failed, and the reasons are many-sided. On the technical side, there are mainly the following eight categories.
① Randomly purchasing seedlings. Many farmers buy so-called “farmed” seedlings or other so-called “high-quality” seedlings from other places, but these are actually collected wild seedlings, and because these seedlings undergo temporary holding and multi-stage storage, transport and other unscientific handling, the mortality rate during farming is 90%——100%. Therefore, when buying seedlings, one must carefully inspect and distinguish them. Generally, for farmed rice field eels, one should select high-quality seedlings locally, which is both economical and guarantees quality.
② Not selecting the variety. By appearance, rice field eels include types such as dark yellow with large spots, earthy red with large spots, light yellow with fine spots, and blue-gray with fine spots. Only by choosing the first two types can faster growth be achieved, and only then can farmed production obtain ideal economic benefits.
③ Mixed farming of large and small eels. When large and small eels are mixed in the same pond, the small eels do not dare compete for food, so their constitution weakens and they may even die. When bait is insufficient, large eels swallow small eels. Therefore, when large and small eels are mixed, although the large eels grow quickly, the total pond output is low.
④ Pond water too deep. Because rice field eels have no swim bladder, they cannot float and stay at will in different water layers to expose themselves to the surface and breathe air. If the pond water is too deep, rice field eels must frequently swim to the surface to breathe, consuming a large amount of physical energy and affecting normal life and growth. For pond culture of rice field eels, according to eel body size, the water depth should be 5——20 cm, while for cage culture of eels, aquatic plants should fill the entire cage to provide good habitat and breathing conditions for the eels.
⑤ Applying manure to the eel pond. The water body of an eel pond is small, and applying manure very easily spoils water quality and induces disease. Such “water quality improvement” is not worth the loss.
⑥ Neglecting to cultivate aquatic plants. Aquatic plants can prevent heatstroke and lower temperature for rice field eels and purify water quality. An eel pond without aquatic plants cannot create a good ecological environment, and farming rice field eels is also difficult to succeed, or difficult to achieve high yield and benefits.
⑦ Feeding “vegetarian” food. Some farmers use wheat bran, rapeseed cake, bean dregs, rice, green vegetables and other plant-based vegetarian foods to feed rice field eels. When severely hungry and lacking bait, rice field eels will also swallow a small amount, but the nutrition cannot meet the needs of their life activities, let alone growth and weight gain, and over time this causes the eels to gradually become thin and weak and to develop disease and die. Rice field eels are bottom-dwelling, ferocious carnivorous fish, and should be fed animal feed or complete compound feed.
⑧ Frequently changing feed. Farmers often change the type of bait fed because bait supply is not guaranteed. Rice field eel feed should have a certain stability. Suddenly changing the feed type makes it difficult for rice field eels to adapt and they refuse to eat, which affects normal growth.