| In my opinion, Flexibacter Columnaris is the bacteria that will cause cottom Mouth Disease. you will see white cotton thick layer on dead tissue on injured koi. normally, algea will get into it and turn it green. Local Temperature play a big role in determine what disease the fish got. If your temp are 90 now, summer time. Your fishes are excused of KHV, Costia and Ich. However, a scope is the sureway. |