This Provisional Instruction identifies chlorine mixosis of carp (Cyprinidae) as an invasive disease found in fish farms of Russia, Ukraine, Kazakhstan, Uzbekistan and some other CSI Member States. Cases of parasitosis have been found in natural waterbodies. The main cause of the spread of this fish disease is the transport of infected fish between fish farms. Another source is the addition of water containing chlorine and infected fish. In cases where chlorine mixosis is diagnosed, fish farms s