The purpose of this article is to examine reef fish aggression and suggest techniques that will allow us to reduce conflict in our saltwater aquariums. In order to understand, and ultimately curb, aggression in reef fish, it is helpful to examine the behavior of these animals in their natural environment. It requires energy, takes time and makes the aggressor more vulnerable to predators. Therefore, aggression must serve a purpose or natural selection would have done away with it long ago. In the highly diverse reef environment, there are limited resources that many fish must defend to ensure their survival.
Reef fish defend food, shelter, mates and offspring from competitors and predators.
Many damselfishes, for example, behave aggressively toward members of their own species or other species that feed on algae, the damsel's primary source of food. These damselfishes defend a specific area, known as a territory, from food competitors. After millions of years of genetic programming, it should not be surprising that these fish do not abandon these behaviors when removed from the reef and placed in a home aquarium. There are numerous variables that will determine whether a fish will behave in an aggressive manner. The aquarist can control or manipulate some of these factors to facilitate the maintenance of peace in an aquarium.