OP, to me both yours look male, but there could be extenuating circumstances not shown with/in only a few photos. If they spawned successfully for the previous owner, I could be mistaken. If not, probably males. To me, expert advice only comes from someone who has kept and spawned a species.
The extenuating circumstances could be that, the female could be the dominant partner, which sometimes allows a female to sport male traits, and appearance (such as a steep profile) especially in caribbean cichlids.
Here is an example, below is a female haitiensus
whenever I took the male out of the tank, within 24 hours, her profile would steepen, and her colors would change. Normally she looked much more female (as the shot below)
Now more to the point Nandopsis male tetracanthus profile
tetracanthus female profile
The extenuating circumstances could be that, the female could be the dominant partner, which sometimes allows a female to sport male traits, and appearance (such as a steep profile) especially in caribbean cichlids.
Here is an example, below is a female haitiensus
whenever I took the male out of the tank, within 24 hours, her profile would steepen, and her colors would change. Normally she looked much more female (as the shot below)
Now more to the point Nandopsis male tetracanthus profile
tetracanthus female profile
