1. Reason: The rotten tail of anchovies may be caused by the lack of timely treatment after trauma, and their tails are fragile. It is easy to be scratched by decorations or aquatic plants at ordinary times. In addition, when the breeder catches, it may also cause their tails to be injured.

2. Treatment: The breeder needs to treat the rotten parts immediately. First, clean up the rotten meat, and then apply some potassium permanganate to avoid re-infection and inflammation of the wound. Finally, use potassium permanganate solution for medicated bath, each medicated bath lasts for 15 minutes, and the unfinished tail can be effectively alleviated.

1. Reason: The tail of anchovies is rotten and the water quality may be too poor, although they do not require high water quality and can live in poor water. However, poor water quality is easy to breed bacteria, which leads to unfinished tail.

2. Treatment: Breeders should first change water to ensure clean water quality, but the amount of water change should not be too large, and it should be controlled at one third of the total water quantity. It is also necessary to sprinkle yellow powder or coarse salt in the fish tank, which can reduce bacterial infection.

1. Reason: Anchovies' rotten tail may also have unfinished tail disease. There are many reasons for unfinished tail disease, and breeders can treat it according to different causes.

2. Treatment: After the breeder judges the cause, he can give the sick fish a medicinal bath with yellow powder or oxytetracycline first. Medicated bath once a day, each time for 15-20 minutes, can effectively relieve the unfinished tail disease.