For reference.
The easiest way to tell males from females, is that females have a dark pigment in the dorsal.
This does not always show up when young.
Dominant males also have a less rounded profile
The H carpintus below were only 1"-2" in the pic.
The dominant male is easy to distinguish.
Here he is below, a little older, note the female in the background (more rounded profile).
another shot of a female, round profile, and dark showing in the dorsal
same pair, much older, male in foreground