The Koran angelfish is a tropical saltwater angelfish that gets its name from a pattern on its tail that resembles Arabic script. It gets its scientific name, Pomacanthus semicircultus, from the pattern of semicircles on the body of the fish as well as from the presence of a spine on its gill cover; Pomacanthus is Latin for thorny cover. The natural habitat of this angelfish is in the ocean around Sri Lanka, Indonesia, the Maldives and the Caribbean.
The fish, when young, is blue and black in color with a white and light blue pattern of semicircles. Adults have yellowish-green heads, with bodies that are brown in the front and back and graduate to yellow-green in the mid-section. There are distinct spots on the sides, pale ones on a dark section and dark ones on a pale section. The dorsal and anal fins have bright yellow tips, and the gill margins and the rings around the eyes are a bright sapphire blue. In size, the fish can measure from one inch (2.54 cm) to eight inches (20.32 cm).
Its attractive appearance makes the Koran angelfish popular as a freshwater aquarium fish. It is quite a hardy creature in comparison with other angelfish varieties, but it is important to keep it in a spacious freshwater angelfish tank, one that is at least 100 gallons (378.54 liters), and to ensure that the water is kept clean and well-oxygenated. Lack of space can aggravate the aggressive tendencies of the fish, and lack of clean water can make it susceptible to disease and pests.
These angelfish are not suitable for a coral reef tank as they tend to eat coral. Aside from coral, they eat worms, shrimps, shellfish, squid, sponges and also vegetables. The Koran angelfish is a grazing fish, which means it will need to be fed several times throughout the day.
The Koran angelfish is rather aggressive and territorial, and it is usually advisable not to keep it with other angelfish varieties, or at least not angelfish of the same sizes. It seems to get along well with fish of other species though, provided, given its territorial nature, that it is introduced last into the tank. It is a good idea to float the angelfish in a transparent container into the tank and see how it reacts to the other fish before releasing it. Providing adequate hiding places and escape compartments for the other fish in the tank is also recommended; if the Koran angelfish seems too aggressive, it may be best to remove or isolate it. This type of fish is not easily bred in captivity, but, if it does, it scatters its eggs.