Very few fish show sexual dimorphism, out of those few the Lamarck Angel, Genicanthus lamarck, is one of them. Both males and females have the same silver/grayish body color with horizontal stripes running from the front to the back of the body and a black spotting pattern on the tail. The difference in the sexes here is that the female has one much bolder stripe running along the body and into the tail. 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.