Hard to tell from the photos but I suspect nothing is wrong with him. Their natural colouring is brown and, depending on genetics, it may be a result of him reverting, or partially so, to his natural colour - like goldfish change colour as they age. It may stay like that or the dark colour may spread. If there is no redness or extra raggedness to the fin I would say he's fine. Their pectorals can get a bit tatty anyway as they dart in and out of tight places.
I am interested in the wide red patch on top. One of mine has that too and I figured it was a result of him ramming himself into a tight hole and scaping the top of his body but perhaps it is normal. It comes and goes on mine and doesn't seem to affect him health-wise anyway.