Some of the stomach content observation of both Maskaheros species showed crustaceans, insect larvae, and detritus.
The waters they are found in are high in pH and mineral content (ph 7.8 and above), and devoid of plant life (except algae).
I have kept both, and found them to be very aggressive, at maturity, unless a swift current is the norm.
I tried to keep them in a cichlid community of 150 gallons and they tried to kill all others, to the point of having larger managuense and dovii, pinned into corners. The argentea ended up alone. I tried them again years later, same result.
I gave the mature regani to a friend for a 220 gal thinking it might be enough, the regani killed his large Amphilophus (mid evil) and carpintus.
Nicaraguense I've kept have been rather benign in a cichlid community setting as far as aggression goes, and worked great in hard water.
On the other hand, both Hoplarchus, and Hypselacara, are soft water species with a preferred pH range under 6.