The following is also from INC. When we first became associated with Toshio Sakai he spent a lot of time teaching us how to care for Koi so that we would be better prepared to keep them healthy and deal with problems as they arise.
We would like to share the way we normally treat the Koi of our ponds when they suffer from localized scale extrusion in small areas. It must be noted in haste, that Koi can be generally healthy yet can still develop small bumps that are infected raised scales. The infection is located under the scales. This condition may be detected by inspection. Figure 1 illustrates how these raised scales might appear.This infection under the scales must not be left untreated. The infected soft tissue under the scales needs to be removed. In the following figures please note the sequence of the procedures that we had taken when we operated on this valuable Showa in January 2002