1. Enteritis: The red-tailed black shark had no obvious symptoms at the initial stage. After careful observation, it was found that the red-tailed black shark was sluggish, stopped at the corner of the tank and did not move, and the body muscles twitched for a short time.

Treatment: The red-tailed black shark was soaked with 0.2 g of nitrofurazone powder, and the red-tailed black shark could gradually return to normal after 2-3 treatments.

2. Tuberculosis: if it develops outside the body, the red-tailed black shark The shark's skin will have some lumpy pale cloudy spots; in vivo, there will be yellow lesions in the internal organs of the red-tailed black shark.

Treatment: Sick red-tailed black sharks should be treated as soon as possible and quarantined. Then use tetracycline solution for medicated bath, and sterilize the water body of water tank with sterilizer.