Hello & welcome to Just Answer/Pearl. I am Dr. B, a licensed veterinarian and I would like to help you with your fish today.Have you checked the water parameters (pH, nitrites, nitrates, ammonia) of your pond? When? What were your findings?
Are the sores always in the same location?Any red streaks on the body, fin or tail ?Any elevation in respiration?
Or changes/inflammation/reddening of the gills?
If possible, can you post a photo of these lesions. This will allow me to see what you are seeing. This can be done either via the paperclip icon on the tool bar or you can post to a photo server (ie flickr, photobucket, etc) and post the web address here.