This comment is absolutely outrageous. Yes, steelhead are tough, but there is NO WAY you can determine, with any certainty, that the gills of that fish were not damaged by looking at a picture. You don't know what happened to the gills when the fish was being attached to the stringer, hung up, and then detached and eventually let go. You also don't know if there was any transfer of bacteria from the stringer to the gills. You also don't know if the fish's protective slime was removed from being handled, which also increases the chance of a bacterial infection (and no a fish does not immediately die from a bacterial infection; it is a slow death). I don't care how "tough" a fish is, damaged gills (you said it yourself) or a bacterial infection will kill any fish. Yes, the fish might live, but definitely not with the chances it would have had if the fish was properly handled.
Grampa Ron, I'm not trying to attack you in any way. That is an awesome fish and I applaud you for catching it. I also understand that a C&R fish is not guaranteed to live even if it was properly handled. I'm just trying to point out, and educate others on this board, that if you're going to put a fish on the stringer you should keep it. If you're going to let it go, it should be properly handled (wet your hands before touching, try to keep it in the water as much as possible, etc.) and not put it on a stringer.