Angelfish reproduce sexually: a male and female engage in brief periods of courtship, which ultimately result in the fertilization of eggs. Angelfish males are quite territorial and defend their territories dutifully, leaving only to mate with females during the spring breeding season.
When beginning courtships, male and female angelfish change color. Females adopt blander shades, turning tan or light brown, while males' mouth areas turn white; their surrounding facial masks turn dark blue. Angelfish mate at dusk and swim rapidly to the surface to do so. The eggs that are instantly fertilized after mating are then released into currents to be carried into the open ocean where ideally they hatch and survive.