The Eibl’s angelfish (Centropyge eibli) is a pygmy angelfish found throughout the tropical Indo-Pacific region. It can also be referred to as the blacktail angelfish or orange stripe angelfish, but it is most commonly known by its scientific name; most retailers simply label it as an Eibl’s angel. This species is easily identified by its gray body and black tail area. It has vertical orange bars, orange pectoral and pelvic fins, and an orange ring around each eye. It can sometimes be confused with the half black angelfish (C. vrolikii), which is colored similarly but without orange bars. Watch specifically for buoyancy issues with Eibl’s angels, as newly imported individuals can often show swim bladder issues from capture. It is also common to see ich or internal parasites in pygmy angels, so be sure to quarantine them.Aquarium requirements: Centropyge eibli normally only grow to about 4 inches in captivity. Despite their small size, however, pygmy angels graze constantly and appreciate large tanks. A 50-gallon aquarium or larger is best. This is not an absolute rule, and many hobbyists do keep pygmy angels in smaller tanks with some success. If attempting to keep this species in smaller systems, be sure the fish is accepting many types of prepared foods and include a lot of well-established live rock for sustained grazing. Compatibility: The two biggest issues with Centropyge angels is whether they can be mixed with other pygmy angel species and whether they are reef-safe. The answer to both questions is sometimes but not always. Pygmy angels are unpredictable, and individuals of the same species can have different temperaments and dietary preferences. When mixing pygmy angelfish, provide a large tank with plenty of habitat and a lot of available food, and introduce specimens at the same time. Similarly colored and shaped species are more likely to fight, so be especially cautious when considering species like C. vrolikii with an Eibl’s angel. Many hobbyists report that including a few different species in a tank is better than just two, but fights are always possible and can unfortunately be quite brutal or lethal. Eibl’s angels often pick at corals and clams, so I don’t consider them to be reef-safe. Centropyge angels can often start to nip corals after several months of ignoring them, and this phenomenon is not predictable. Despite this, however, there are many success stories of keeping pygmy angels in reef tanks, and these small gems are certainly very tempting for such setups. If you do decide to keep this species with corals, it is probably best to choose soft corals (leather corals or mushrooms) and avoid fleshy stony corals and tridacnid clams. Feeding: The biggest hurdle to getting this species to thrive is proper diet and frequency of feedings. Eibl’s angels can be reluctant eaters. In addition to grazing live rock, however, they will usually transition to frozen foods, such as enriched brine shrimp, Mysis shrimp or Cyclop-eeze. Many individuals also accept dried algae, either in sheet or granule form, and most will eventually take pellet and flake foods. While it used to be difficult to find good food items for pygmy angels, there is now an array of options on the market for balanced nutrition. The challenge now isn’t really the quality of food but the quantity. Pygmy angels on the reef spend nearly all of their time grazing small bites of algae and invertebrate tissue, so the transition to a captive-reef aquarium, where meals come only a few times a day, is a challenge. Provide small, frequent feedings for an Eibl’s angel, and vary their diet as much as possible. Foods containing a lot of plant material are important, and many brands of frozen food are marketed specifically for pygmy angels. Regularly supplement their diet with vitamins, especially for frozen and dried foods. Breeding: Captive breeding of pygmy angelfish is picking up steam in the hobby, but C. eibli has not yet been bred successfully. Although I suspect that breeding success with this species isn’t far off, I have no doubt that it will be a long time before commercially raised Eibl’s angels are available with any regularity. Notes: A fascinating case of mimicry can be observed with Eibl’s angel and the mimic tang (Acanthurus tristis). The juveniles of A. tristis display identical coloration to the Eibl’s angel, though they don’t maintain this color as adults. It is unknown what the advantage of this coloration is for the tang, but it is quite attractive, and A. tristis is somewhat regularly available. These species shouldn’t be kept together, as the Eibl’s angelfish will normally act aggressively toward the mimic tang. FAMA STEVE BITTER is a senior aquatic biologist at The Florida Aquarium in Tampa, Florida. His areas of interest include fish health and quarantine, scuba diving and coral reef restoration. .