I would keep an eye on these, they do not look like marks from trauma, as you suggest. These holes, especially the holes around his nostrils, are textbook HITH holes. I'm not trying to argue with you, I'm only telling you what I know to be true in my own experience. There is a parasite which is also associated with HITH... it is not always due to bad water quality. Though you don't provide params., I think it's pretty obvious that you keep this guy the right way. However, have you ever looked into Hexamita? As I said, it might do this guy good just to do some checking, because these don't look like holes from injury, especially the ones around his nostrils.