Angelfish are considered by many to be the most beautiful fish associated with coral reefs. The genus Centropyge is the largest in the family Pomacanthidae. It is comprised of two subgenera and approximately 32 species. The largest Centropyge species attains a maximum length of 7 inches, with the average adult size being closer to 4 inches.
All pygmy angelfish are protogynous hermaphrodites (all males result from female sex change). Sexual metamorphosis is socially controlled by the presence of a dominant male. A female may engage in early sex change if there are many more females than males. All pygmy angelfish are haremic. Harem-groups are usually composed of one male, one to four mature females and up to nine immature females. The dominance hierarchy is a size-based linear dominance hierarchy.
Dwarf angels are known prey items for many larger reef fishes. Which explains their inquisitive and alert behaviour. Placing these kind of fish with larger predatory species should be avoided (ie: Groupers/Bass, Lionfish, Triggers). The most Dwarf angels do not adjust well to aggressive tankmates.
All Centropyge consume a considerable amount of microalgae and detritus, therefore it pays to not be too meticulous in keeping their system sterile. Allow algae to grow on the surface of all non-viewing panels of the system and decor. One species that seems to be particularly fond of Caulerpa shoots is the flame angel (C. loriculus). Several species also feed heavily on the feces of other fish. In the aquarium, some Reefer have seen a number of pygmy angelfish engage in this feeding mode, known as coprophagy.
No matter what species you are thinking of adding, remember that introducing any angelfish to your reef aquarium always entails some degree of risk.