Does the fish flare its gills when it sees its reflection? If it does, look at how extensive the gills are. Just at the side is a female; at the sides and under the chin (so it looks like a beard) is male.
Definitely a female, been breeding these fishes for a long time. Males would have a fuller, bigger and better-shaped body. Their tail should form a D shape too, that one also has a stomach that looks like a female
you can see it in the body shape