That looks more fungal to me and I would treat by catching the fish and sedating it with oil of cloves to keep it from hurting itself during treatment and then using a small paint brush, rub table salt on the areas to remove them, and then treat with iodine before returning to the pond.
It would be a good idea to get teat results for ammonia, nitrite, pH morning and evening, KH and temperature to let us see what the water quality is. Clear water is not necessarily good water and your water if very clear.
Is the pond a rock bottom pond? How old?
Zone 7 A/B
Keep your words sweet. You never know when you may have to eat them.
Richard