The Japanese eel  

 In that case, it might be more accurate to call Japanese eels Asian eels, because eels that grow in America are called American eels and eels that grow in Europe are called European eels.  

Characteristics of the Japanese eel

Eel shaped like a snake, slender body, near cylindrical front, tail slightly flat. The Japanese eel has the longest body, followed by the European eel and the American eel.

 Eel body color is related to feeding environment, water quality and feed quality. Usually adult eels, Japanese eels are dark gray or gray-black on the back and white without spots on the belly; The European eel has a silver-gray back and a nearly white belly without stripes. 

The American fish is similar to the Japanese eel. The body color of eel is related to different stages of growth and development. 

In the adduction stage, the whole body of eel larvae is white and transparent, so they are called white larvae, glass broken or broken lines. After about 2-4 weeks of feeding, the juvenile eels gradually turn pale black, and then they are called black larvae. 

The eel's skin is composed of outer skin and scales, and its surface is rich in mucus, making its whole body very smooth. Eel scales are buried under the skin and are not usually noticed.

Eels like the temperature

Eels are warm water fish and cannot withstand high temperature. The optimum water temperature for growth is 10-30 ℃, and the optimum water temperature for growth is 22-28 ℃. 

When the water temperature rose to about 10℃, the eel began to feed: when the water temperature was 16-28 ℃, the feeding was vigorous and the growth was rapid. 

When the water temperature was over 29℃, the food intake decreased significantly. When the water temperature drops below 5℃, eels go into stiff hibernation. 

Eels react abnormally when the water temperature rises to 35.5C, and 38.5 C is the lethal temperature for eels. 

Eel has strong adaptability to the change of water temperature in the suitable temperature range. 

However, the temperature difference should be controlled within 3℃ to ensure the normal growth of cultured eel when adding water or pouring water in slow pond

Eels like to eat

Eel is a carnivorous fish, and its feeding habits vary with the different growth and development stages of eel. 

Generally, white eels take rotifers, water fleas, earthworms, larvae of aquatic insects and similar residues and organic debris as bait. 

The young eels with a body weight of more than 5g can actively prey on small fish, shrimp and aquatic insects, etc., and can take the combined bait. However, adult eels with body weight over 100g can mainly feed with bait, and also prey on small fish, shrimps, crabs, shellfish and other aquatic insects in cultured waters. 

The feeding intensity of eels is related to temperature. When the water temperature rises above 12℃, eels start feeding, while when the water temperature drops below 12℃, eels stop feeding and enter hibernation.

 When the water temperature is 22~28℃, the eel has the highest feeding intensity, with daily intake accounting for 5%~10% of its body weight, and the fastest growth rate.