Korans are found throughout the Indo-Pacific and Red Sea, and are likewise collected widely. The species is found foraging and hiding around coral and rocky reefs, not in open, upper waters or over sandy bottoms. You should provide some similar habitat.
Selection; General to Specific:
For most circumstances, Korans, like other large angelfishes, should be purchased as juveniles, but not babies. Very small individuals (less than two inches) should be avoided as they usually adapt poorly. Get at least a three inch specimen; and unless you have the time to expend and the money to gamble, not one over six inches. Larger specimens often time are problematical in terms of foods/feeding and behavior. Also of note, larger specimens (upwards of 16 inches) require systems of a few to several hundred-gallon capacities.
There are a handful of important observational criteria to consider in picking out a good specimen. A prime one is apparent health as gauged by gill movement. A healthy individual displays regular, steady "breathing" of about once per second. Gill flukes, common and species-specific on these wild-caught fish, the effects of "gill-burn" from shipment/handling, poor present water quality, all can speed up the rate of gill movement. Avoid such angels.
Instead choose one with full finnage and a full-body appearance, not thin in the head or stomach. Only buy angels that are alert interested in their environment, not skulking in a corner. These pomacanthids have a curious nature that mirrors their intelligence.
The fishís color should be bright and uniform, showing no light spots, blemishes or pitting. Eyes must be clear and shiny.
Ask to see the prospective purchase eat what you intend to feed it at home. Though most Korans that eat will live on, itís best to leave the specimen for weeks stay at the dealers holding it on deposit.
Environmental Conditions; Chemical, Physical, Biological:
Koran angels are more sensitive to poor water quality as marine aquarium species go. Excess organics often show as blotchy white-marked areas, and are directly positively correlated with ease of infectious and parasitic susceptibility.
Temperatures in the low to upper seventy degrees Fahrenheit, lower to "normal" specific gravity (1.018-1.025), of natural or synthetic saltwater are fine. Effective protein skimming is a must have.
All members of medium and large angelfish species are aggressive toward their own kind, other angels and similar-appearing fishes and are ideally kept one specimen to a tank. Moenich offers comprehensive advice on mixing angelfishes. Sometimes adding them at the same time, moving around parts of the habitat, disrupting territories, or bringing in ever-larger specimens can successfully mix these angels. This practice is not encouraged unless you have other facilities for separating them, should relations sour.
In most cases other non-angel species are generally ignored; occasionally a Koran angel will become a bully, and require "rehabilitation" through removal or temporary isolation. Provide adequate hiding and escape spaces for tank-mates and observe your charges, as you should, daily.
This is the most critical area in keeping most angels and many other saltwater species. Koranís should be offered live and fresh foods and weaned from natural foodstuffs ASAP to survive and thrive. In the wild, Korans feed on algae and associated fauna primarily as juveniles; adults eat copious amounts of sponges, corals, and algae with the remaining bulk made up mostly of worms of all sorts, crustaceans and mollusks. They supplement this diet well in captivity with crustacean and other fresh and frozen animal foods.
Opened, whole shellfish, squid, frozen and fresh crustaceans
should be offered occasionally. Plant material/algae materials should be fed daily. Algae (Caulerpa, Ulva (sea lettuce), Nori and kombu from an oriental food supplier, et al.) and plant matter (spinach, zucchini, chard etc.) should make up a substantial part of their diet. Feed frequently, small amounts.
Infectious, parasitic, nutritional and social diseases are a significant problem with this species. Beyond details already listed, careful handling, quarantine and freshwater dipping with or without admixtures are recommended. If necessary, copper treatments (best chelated types) are suggested for ridding pathogens.
The Koran or Semicircle Angelfish, Pomacanthus semicirculatus makes an excellent first or beginner angel for aquarists with an adequately large system. It's easy to find, reasonably inexpensive; simple to maintain when purchased at the right size and fed properly, intelligent and long-lived.