The pattern of that fish. IMHO, is 100% northern pike. As Bill said, the best way to tell is check for scales on the lower cheek but I think this fish shows a lot of NP characteristics and no obvious musky ones. Are we thinking someone photoshopped the pattern on a musky?
Some generalizations I have found are that musky have more red in the fins, musky's spot pattern is less obvious with the spots being dark not light, pike are more green on the back while musky are often silver to bronze.
It does seem like there's something off with the picture. Maybe that guy 5'2" and 100lbs? The girth on that fish is IMPRESSIVE.
