Grass carp

How do we tell weather the grass carp gets ill or not? Or what's the symptom of each disease respectively? What should we do with these symptoms to prevent us from loss? Extracted content: Viral hemorrhagic disease Symptoms: Spots or masses of hemorrhage appear in various tissues, organs or tissues on the surface of the sick fish, and even hemorrhage throughout the body. After the epidermis is torn off, the whole body muscles can be seen red. The gill filaments are bleeding or pale, sometimes there is ascites in the body cavity, there is no food in the intestines, hyperemia but not erosion.