Looking at the pictures, it would appear that the fish has scraped the scales, maybe backing out of a skimmer. There appears to be some infection and that will require the use of antibiotics. Before we get too far into the one fish, it is always good to have some numbers to see what it going on in the pond. What is the pond volume? How many fish? Any others showing similar signs? What is the ammonia, nitrite, pH and KH test values (real numbers, not just good)?
Zone 7 A/B
Keep your words sweet. You never know when you may have to eat them.
Richard