Needle tail. At first, I saw the white-lipped hanging irritable, with all the fins tightly clamped, and when swimming, it was serpentine or only flicked its tail and did not move forward very much, as if struggling. The angle of the caudal fin is obviously reduced, and in severe cases, it shrinks into a cone. The fish constantly shakes their bodies and likes to gather in the corners of the water surface or bottom. The diseased fish will not die soon, but it will affect their feeding and development.

Isolation treatment. Oxytetracycline or chloramphenicol is made into an aqueous solution with a concentration of 1/100,000, and the diseased fish is soaked in it until the symptoms disappear. Sprinkle the whole tank with saturated salt water. Add one milliliter of saturated saline per liter of feeding water, raise the water temperature to 28-30 degrees, and add yellow powder if necessary to prevent secondary bacterial infection.