Yes, females almost always have a black blotch in their dorsal fin (though not 100%) and sometimes have a black spot on their cheek. Lacking both, I'd go with male. It does seem to have more red than a lot of males have, but with the fin length as well as the lack of black spots I'd still lean towards male.
Male. No black blotch in the dorsal or black spot on the operculum. Not %100 every time but there's also too much blue sheen thrown on top of it which also leans more towards male.