Hi Johnm,
Here is a progression for you to study. This is only one possible scenario though. Showas are fascinating and complex. I work with 5 different styles of sumi here,... and each develops differently. It's important to identify the type of sumi on Showas,... then you'll have a better idea of how it will mature over the years. Beyond the type of sumi, the sex of the Koi will influence this, and the environment, as well as diet.
The Showa in the pics is a male.
Best Wishes,
Brady Brandwood
