Very few fish show sexual dimorphism, out of those few the Masked Swallowtail Angelfish, Genicanthus semifasciatus, is one of them. Females will display a creamy white color bottom half that fades to yellow towards the top half with a black band just above the eye and on the tail. Males will display more of a yellow/orange color beginning at the face and along the body with black vertical striping. Since they are more peaceful than many other Angelfish, they can be kept as a mated pair, or in a small school of females. Avoid keeping two males in the same tank, as it can lead to extreme aggression.
These Angelfish are also unique in the way that they are reef safe, and will not nip at soft and stony corals, or sessile invertebrates, making them a great choice for an Angelfish in a reef tank setting. Diet should include a variety of spirulina, marine algae, high quality angelfish preparations, mysis and brine shrimp, 3 times daily.