Aggression is an adaptive behavioral trait that is important in the competition for mating partners, food, and territories and in the establishment of social hierarchies. Dominance hierarchies not only reflect fitness, but also prevent the need for continued aggression and associated risk of injury. Therefore, aggression is also a trait under stabilizing selection. From genetics perspective, aggression is a quantitative trait. High heritability estimates for aggressive behavior have been observed in many species, including human being. Similar to other behaviors, the display of extent of aggression is influenced by a combination of genetic and environmental factors. To understand the genetic architecture of aggression, it is necessary to integrate human genetics studies with studies on other organisms. Herein, we reviewed the molecular pathways and gene types related to aggression in fish, including 5-hydroxy tryptamine, dopamine, histamine, somatostatin, nitric oxide, hypothalamo-neurohypophysial, hypothalamo-pituitary-interrenal, and hypothalamo-pituitary-gonadal pathways, and several other genes. Furthermore, we also describe the discriminant method of aggression in fish, which provides a theoretical basis for further studies in the molecular regulation mechanism of aggression in fish.