You have very white/bright substrate which tend to wash out colors on most cichlids.
With bright substrate some cichlids never show normal coloration, but many come around as they get comfortable.
Color pattern can help "suggest" gender in managuense, so trying to tell against that substrate just makes it more difficult than normal at the 3" size, if you can get a shot with normal color, it would help.
Males tend to have spots on the lower jaw, and are more spotted, females less spotting on the jaw, and a more blotchy pattern.
Below is Parachromis motaguense, very close cousin, and gives an example of what I mean.
Male below note the spots on the lower jaw, and gill plate.

now a female, lack of spots, on jaw and gill plate

together, Moore the females more blotchy color pattern.

Both these are mature, female @ 6-7", male 10-12", so at that stage of maturity, much easier to see gender difference, also note hi taller more bulky body size, all these are similar traits found in managuense.