I posted a new picture of the damaged fish:
http://homepage.mac.com/pondstuff/PhotoAlbum1.html

The left side of the fish now appears to have healed. The blood by the
right eye is also gone, and the damaged area on the right gill looks
much better. The upper-right-center area continues to show a lot of
damage. Looking at the old and new pictures, does that area appear to
be healing OK on its own?

The fish is active again today.

Thanks for the feedback on my microscope observations & the links.

Dave