Because most cichlids exhibit aggression during breeding and territorial defense, a common solution to reduce such aggression in closed systems is the introduction of sightline barriers. This can come in the form of plants, rocks, wood, decorations, or even sand piles. The basic principle is that blocking the regular view of one cichlid from another will reduce aggression between the two. However, relying solely on sightline reduction to mitigate aggression in cichlids is often futile. Why?