Actually, that's the way things are. It's instinct and how things were planned out. In lake tanganyika, the cookoo species of synodontids have naturally fast hatching eggs so that they can outspeed the cichlids in hatching and growth, and thus, prey on the smaller fry while getting 2 well armed, devoted guardian.
Cichlids have a highly developed social structure which would take more intelligence to conduct. Let's assume that their "intelligence" is just instinct or rather, programming. For example, compare cichlids to neons. If cichlids have a wide variety of actions which are conducted in their social structure, it would take much more memory space than would simply the bare essentials and very few added pluses which is what neons have.