Juvenile Queen Angelfish (Holacanthus ciliaris) are grey and yellow with several blue and white bars on the body. The adult Queen Angelfish has a vivid blue or blue-green body with yellow rimmed scales. The pectoral fins, ventral fins, and tail are entirely yellow. The head has a dark blue spot with a bright blue edge.
The larger angelfish available in the aquarium trade include those from the genera Apolemichthys, Chaetodontoplus, Holacanthus, Pomacanthus, and Pygoplites. Of these, Apolemichthys and Chaetodontoplus are generally the smallest and are sometimes considered "pygmy angels" compared to the much larger Holacanthus and Pomacanthus angels. The Regal Angelfish, Pygoplites diacanthus is the only fish in the Pygoplites genus.
Juveniles and adults among these angels usually have very different appearances and, in the wild, usually live in harems with dominant males controlling a group of females.The color change in angels can be triggered by size, age or a change in social structure. Angels should not be kept with other large angels in the home aquarium to avoid territorial conflicts. Occasionally, two angels may tolerate one another in a very large aquarium if they have very different coloration and appearance, but is not typically recommended.
Suitable tankmates for most large marine angels would be larger community fish like tangs, triggers, groupers, some damsels, butterflies and similar fish. More shy and passive angels can be kept with smaller, more docile tankmates. Be sure to take the adult size of the angelfish into consideration when choosing an angel for an aquarium as many can grow very large (albeit slowly) and need tankmates and an environment that can accommodate them. All angels have cheekspines at the edge of their gill cover and in the dorsal fin. Use caution when handling and avoid using a net that they may become stuck or tangled in.
The diet of large angels generally consists of meaty foods, algae, and marine sponge. Many frozen angel formulas and flakes may have extra sponge meal, and live sponges can be purchased to supplement their diet. These angels are not reef safe and have been known to nip at or eat some corals, sponges, and clam mantles. Some leather corals and anemones may be safe with larger angelfish but is not generally recommended.