This is a tough call, it may be that that this is (or was) "the" dominant fish in the tank, which could make it female, because of its dominance status, and thereby show dominant (often male traits).
The overall coloration seems to be male, but a closer look at the dorsal shows the pigments of a female, and the profile is not quite as steep as a normal male (depending on its size, I can't tell).
So its gender is not obvious to me.
Here is a dominant male I had.

and check out his caudal, the ring in males are sometimes not as symmetric) and spotting on the unpaired fins

Now a female, note the cause ring

same female, in a more dominant place in the cichlid hierarchy, just a few spots on the dorsal and anal fin in comparison to the male.

Now an edited version of your pic, I wanted to bring out some detail, like the dark area in the dorsal, the more symmetric caudal ring, and lack of spotting in both unpaired fins.
