Very hard to say. Simply because structurally, that's a male structure fish. But I've seen quite a good numbers of male body structure fish that is a female(own one myself as of now). In terms of male shaking its head and what not, don't use that to determine if your fish is a male or female. Some males are calm towards different fish, gives a little warning(head shake) and leave it at that. When they see a different male, they may act totally different going all furious. If you want to know for sure, let them lose...just have a net in ready.
P.S. - Most males who see another female goes all nuts like a dolphin in your fish tank.