I agree with Frank, the Herichthys looks to be female.
Females have a black area in the dorsal, and I think I can see it, although your pics are not clear enough to be sure. A shot with the dorsal extended, and a good side view o its cranial profile.
Males have a more steep profile. Below are examples.
female, note the black area in the dorsal, and torpedo shape profile

male below, note steep profile, and lack of dark color in the dorsal