Multiple selective pressures affect swimming performance of fish. Among these are abiotic conditions of the physical environment, such as temperature, salinity, and flow velocity, and biotic interactions, such as competition, predation, and parasitism. Both abiotic and biotic selective pressures have shaped the morphology and physiology of species and/or populations. In addition, sexual selection acts on male swimming performance to modify size and shape of the body and fins. Here, I focus on: (1) how sexual selection, acting within the framework of ecological, morphological and physiological constraints, influences swimming performance (2) how secondary sexual traits of males, such as enlarged fins, affect different aspects of swimming performance, such as endurance, agility, and burst speed (3) how environmental factors constrain the evolution of energetically expensive courtship displays and (4) how scaling issues, such as interactions between body size, sexual size dimorphism, secondary sexual traits, courtship behavior, and metabolism affect swimming performance.