In your first pic the one on the left looks female, the darker bars tend to be a female trait, but could also be traits of a less dominant male.
And the right looks to be alpha male, less barring, and maybe a steeper profile.
But clear close ups would help in a more accurate gender ID, where the profiles were much more obvious, differences are often subtle so you need to show photos that present those differences.
Here are examples
a pair of N tetracanthus, note the males steep profile, and females torpedo shape.
P motaguense, even though the male in the back is out of focus, his profile obviously contrasts with the female
and because managuense gender differences are often more subtle, this is the reason your photos need to be more concise, obvious, and closer.
And I agree with robham777, a pair of managuense in a small tank like 55 is asking for a dead female
