Angelfish, which might be termed “classic marine aquarium fish,” are vibrantly colored, active, and alert (see color insert for photo). Some species also grow to be quite large, attaining a length of 24 inches or more. If you have an aquarium of 20 gallons or less, you might consider keeping one of the dwarf species of the genus Centropyge, several of which are fully grown at 4 inches or so.

Although some of the dwarf species such as the cherubfish (Centropyge argi) are fairly hardy, angelfish are not, as a rule, recommended for hobbyists without considerable experience in keeping marine fish. Nearly all of the approximately seventy-five species are, in general, intolerant of suboptimal water conditions. Many species are fairly specific in their food requirements as well, subsisting largely on sponges and corals in the wild, which makes them difficult to acclimate to captive diets.

Sponge-and coral-based foods are becoming easier to find, which makes your job of feeding them easier. Well-acclimated individual angelfish can actually become tame enough to take food from your fingers. In addition to sponge, coral, and algae type foods, angelfish should be offered a wide variety of live and dried foods, including brine shrimp, mysid shrimp, squid, prawn, and mollusks.

Despite their predilection for active swimming, all angelfish require rock work and coral where they can find shelter at night. Dwarf species in particular require a great deal of structure in the aquarium. Much of their time in the wild is spent swimming around similar structures. Deprived of secure hiding spots, most will languish and die.

Although captive breeding is an extremely rare event, several species of angelfish have successfully reproduced under captive conditions. All species, as far as we know, reproduce in pairs. Outwardly very similar, the sexes may sometimes be differentiated by the swollen abdomen of the pregnant female. Mated pairs of angelfish rise upward together, releasing eggs and sperm as they go. The tiny eggs float about among the plankton, and, after a time (which varies from species to species but averages approximately one month), the minuscule fry settle to the ocean's floor.

Vividly colored even for an angelfish, the flame angelfish has a brilliant red body with blue stripes, making it instantly recognizable to most aquarists. Inhabiting the South Atlantic Ocean from Mexico and Central America to Australia, the flame angelfish is by nature a grazer and should be provided with an ample amount of algae-based foods. The flame angelfish will also readily accept squid, chopped clams, brine shrimp, and other invertebrates. The flame angelfish matures at a length of approximately 4 inches and is a good choice for the hobbyist maintaining a smaller aquarium. It is fairly hardy but does require excellent water quality in order to thrive.

Well deserving of the title “queen,” this attractive fish has a yellow-green body outlined in brilliant blue (see color insert for photo). Color varies a great deal among individuals, and it has been suggested that this species hybridizes with close relatives. The queen angelfish lives throughout the western Atlantic and Caribbean and is generally found in a mated pair situation. This large (28 inches) species requires a varied diet in which algae and sponge-based foods predominate. It will also relish such items as clams, prawn, and mussels. As with most angelfish, queen angels are intolerant of other individuals of their own or similar species and require a large, well-filtered aquarium with suitable hiding spots.

All angelfish appear to be extremely territorial and, with the exception of mated pairs, are largely intolerant of other fish of the same species. Many will also fight with similar species of angelfish and even with unrelated fish. Except for some of the dwarf species, a large tank does not necessarily guarantee harmony, as naturally sized territories are generally larger than can be provided for in the aquarium.

Angelfish can be distinguished from the superficially similar butterfly fish by the spine that all angelfish carry on the gill cover. Once classified with the angelfish, butterfly fish are more “compressed” in appearance than are angelfish.