I've seen two different sev's call this ... the fairly common Rotkeil aka red shoulder and the rarer Rio Tapajos red nosed greens ... it depends which one you are interested in.
Just a size difference, as Ryan said the temperament is pretty much the same.
It's a male Heros notatus. They are not "red head" or "red face" by any means and you're looking at its final adult coloration, but they are gorgeous fish regardless and one of my very favorite species of severum.