What disease is the body color of breeding red sea bream turning white?

This is lymphocytic leukemia. Some of the farmed red sea bream turned white, swam alone on the surface of the water and had ulcer lesions on the body surface. The fish were dissected and examined for kidney enlargement, green liver symptoms and ascites with blood in the abdominal cavity. The mortality rate of red sea bream can reach 1020%, and no effective prevention and treatment method has been found at present, but when this disease occurs, it should be fed antibiotics and a large number of multivitamins in time, which can reduce death and economic losses.