I'm confused..are they in the divided 90 or a 10 gallon?
I have to admit I scroll up and down looking at the two. I would guess they are very young and not a snap to --- at that size.
At the length you have estimated (I know it's hard to catch them uncurled with your tape measure in hand!) they are probably about 6 months old. Barely sexually mature.
On the male you will see a definite "smooth" area, around his ventral fin.
The first photo is a male, obviously proven. His pouch is quite apparent.
The second is a female. No pouch, or apron. The spines are consistent on the belly.
The unproven male will have a very small smooth area, having not been stretched by a brood.
It is hard to tell without seeing the little beauties!
I do miss my girls.