The harems exhibit a pecking-order hierarchical system of dominance. If the male is removed from the harem, the top ranking female will change to the male sex over a period of only two to three weeks. It appears that harem formation and sex inversion is common among the species of Centropyge and Genicanthus . On the other hand, monogamous pairing is the reproductive unit of the large Pomacanthus and many of the Holacanthus angels. The majority of the spawnings take place between 10 minutes before and 5 minutes after sunset unless it was heavily overcast in which case the activities occurred much earlier in the day.
Courtship consists of rapid ruching and circling of individual females by the male.
This leads to sudden spawning burst in which eggs and sperm are simultaneously released in open water. The eggs are buoyant and float to the surface where they are planktonic for an unknown time. Very little information has been collected concerning the reproductive habits of marine butterflyfish. What is known is that, like the angelfish, they produce small buoyant eggs that float to the surface after their release. The larvae known as Tholichthys are covered with bony plates and are pelagic for periods ranging from a few weeks to several months.