Throughout my fish keeping journey over the past two decades, I have kept many species of cichlids. We know that every cichlid has its own personality. We also know that the size of the fish is not indicative of its aggression level (e.g., not all big fish are mean and not all little fish are friendly). In fact, some of the nastiest species I’ve kept are dwarf species.
There are lots of variables that affect a cichlid’s aggression. Did you know that physical body colors is one of them? Some recent research using Pearl cichlids (Geophagus brasiliensis) as a model investigated how body coloring might affect territorial aggression levels.