One distinct feature that enables one to tell the difference in gender between male and female Parachromis, are distinct dark spots on the gill plate of males, and less distinct smudges, or naked gill plates of females.
Your pic is not close or sharp enough in detail to really show what is needed to be seen.
I tried to edit it to tell, but that made it even somewhat less distinct.
And this characteristic often doesn't present until a certain age.
You don't give the size or age, which could also help.
Although the Parachromis below are not managuense, they are a close cousin, that shows the spots that are generic in most Parachromis species.
1st a male, note the spots on the gill plate
now a female below, note the lack of any distinct small markings.