Hi Graham, I didn't know what the problem was when I took this pic. I put it up here for anyone to offer an opinion with a link to they yks forum. I did numerous scrapes but found nothing at all. The marks are actually below the scales, at first I thought this was some form of sepsis, causing the fish to haemmorhage through the tissues, but quickly realised the fish was too well. Eventually I found a few anchor worm, and I have treated for this around 5 days ago. The fish is now healing well, with broken tissue below just one of his scales, so hopefully I'm on top of this now.
