Before making a determination, I'd like to see the dorsal fin extended, as opposed to closed like it is in both shots.
Because a dark area in the dorsal is usually the best indicator.
I think I see color in the dorsal, but still very hard to see.
Here are 2 females.
But if a male is not present the distinction can be blurred.
Below is one of the same females as above, but without a male in the tank.