A Detailed Guide to Common Eel Diseases and Prevention and Treatment Methods

The eel is a common fish. What makes it different from other fish is that its body is very long, like a snake, and very thin with no scales. Eels can effectively dispel cold, and they are rich in nutrients such as vitamins and minerals. As eel fishing has become increasingly widespread in recent years, eel numbers have gradually declined. Artificial farming has therefore become popular, but artificial farming brings many diseases. So what diseases are there? How should they be prevented and treated? Let's take a look!

1. Tail rot disease

Disease characteristics: Tail rot disease is caused by infection of wounds on the body. After onset, the skin of the diseased fish peels off as if shedding, and the flesh also begins to rot. It generally occurs below the neck and around the mouth. The diseased fish is weak and powerless, and the rotting area begins to darken in color. In severe cases, the tail directly rots off, and the fish bones and flesh can be seen exposed. It occurs less in winter and mainly affects young fish.

Prevention and treatment methods: When purchasing fry, observe whether the fry have wounds, and be careful during transport to prevent the fry from being injured. When stocking, carefully check for diseased fish and fry that died during transport, and remove them to prevent the spread of disease. The fry also need to be disinfected before being put into the pond. Diseased fish can be soaked in formalin for treatment.

2. Enteritis disease

Disease characteristics: Enteritis is caused by infection of the eel's gastrointestinal tract, generally brought on by overeating, moldy feed, poor water quality, or insufficient dissolved oxygen. These are all caused by improper management by the keeper, without a reasonable feeding method. The appetite of the diseased fish gradually decreases, diarrhea occurs, and in severe cases it dies. In dead eels, redness and swelling can be found at the anus, along with a very foul odor, and the fins are congested. It generally occurs in adult fish.

Prevention and treatment methods: Develop a reasonable feeding plan, feed at fixed times and in fixed amounts, observe changes in water quality, and change the water and add oxygen in time. Control the stocking density of the pond; if conditions permit, add an oxygen injection device beside the pond. After onset, reduce the feeding amount and mix an appropriate amount of chloramphenicol and other medicines into the feed for treatment.

3. Saprolegniasis

Disease characteristics: Saprolegniasis, as the name suggests, is caused by infection with Saprolegnia, which is a fungus. It generally occurs when eels are injured and their resistance is weak. The incidence rate is highest when the temperature is relatively low. White lines appear on the tails of diseased fish, and more mucus is secreted on the skin. Diseased fish have difficulty swimming, their appetite decreases or they stop eating, and they eventually die. It usually occurs in young fish, and the mortality rate is relatively high.

Prevention and treatment methods: As with tail rot disease, check for diseased fish when purchasing and transporting fry to prevent injuries and wounds during transport. Before stocking, wash the fry with salt water. The pond should be disinfected frequently; formalin and other solutions can be used for disinfection. After onset, raise the water temperature in time; it must not be lower than 25°C, and about seven days will suffice. Furacilin and other medicines can also be used for soaking and washing.

The above are the diseases that commonly occur in eel farming. These are all pathogenic infections, and there are also parasitic diseases. For example, trichodiniasis: Trichodina feed on cells on the gills and surface, causing the eel's appetite to decrease and making it very prone to triggering other diseases. The pond should be disinfected in time, diseased fish should be removed, and pond management should be strengthened. That is all for today's introduction. This article is for reference only. Thank you everyone for reading and supporting.