The Queen Angelfish is a deep bodied, highly compressed fish with a blunt, rounded head and a single continuous dorsal fin. It's lifespan in the wild is about 15-20 years. They are kept in aquarium tanks for their beauty, but are difficult to keep, because they need a big tank and can get aggressive.  
The Queen Angelfish, like other Angelfish, has a long tail behind it. It has a thin body which allows it to turn quickly. It gets it's name from a black spot on it's forehead, circled by a round blue circle, that looks similar to a crown. They are a brilliant blue and have a bright yellow tail, with a yellow rim and pectoral fins. They have hints of purple and orange. It's mouth, chin, throat, chest, and abdomen are a purplish blue. Their colors change as they grow. The juvenile has a darker body with blue bars and yellow highlights. Although their colors are bright, they blend in with the exotic coral reef. They have a small mouth, round head, and square caudal fins. Queen Angelfish also have binocular vision. They can grow up to 18 inches in length. Their weight is about 3.5 lbs. There is little known difference between the males and females, except that the males may grow larger.   
An interesting fact about Queen Angelfish is that they are often found in pairs and that they mate for life. They reproduce by floating up in the water, while bringing their bellies close together and releasing a cloud of eggs and sperm. The female can release from 25 to 75 thousand eggs each evening, which can equal up to 10 million eggs in each spawning cycle. The transparent eggs float in the water column and are pelagic and buoyant. The eggs will hatch in 15 - 20 hours. When they hatch into larvae they won't have a gut, good eyes or fins. The larvae is attached to a large yolk sac that is absorbed after 48 hours. During this time the larvae develop normal characteristics of free swimming fish and begin to feed on plankton in the water column. The larvae grow rapidly and 3 to 4 weeks after hatching the fish will be 15 to 20mm and will settle on the bottom of the sea.
The Queen Angelfish (Holacanthus ciliaris) is very similar to the Blue Angelfish (H. bermudensis). The two species have been known to interbreed, creating a hybrid that shares the color characteristics of both species. The hybrid is rare and, unlike its parents, that swim deep down in the sea, it swims in the reef tops.
The Queen Angelfish lives in coral reefs in tropical western Atlantic waters from Bermuda to Brazil and Central America. They are abundant in the Caribbean.
This angelfish stays near the bottom in coral reef habitats and is non-migratory. You can find it in near shore shallows down to the deepest part of the reef. Queen Angelfish are generally solitary or found in pairs through the gorgonians and corals of the reef. They are territorial and can be aggressive with other angelfish, especially other Queen Angelfish. They are a shy fish, but occasionally become curious.
Queen Angelfish are omnivores and they mostly eat sponges, but they also eat other things like: jellyfish, tunicates, plankton, algae, and corals.
The juvenile Queen Angelfish will set up cleaning stations along the reef and larger fish will let them come and clean them by eating the plankton off of them. Even when the larger fish is known to be a predator, it will remain motionless and allow the smaller fish access to sensitive areas.
The Queen Angelfish is effeted by the ciguatera poison. It is caused by accumulation of ciguatoxins in fish when ingested. Dinoflagellates produce ciguatoxins that grow on algae. Then the fish eat the algae and it gets into their flesh and into the larger fish that eat them. When humans eat these fish they get ciguatera poisoning which is serious and can last for weeks. The symptoms are weakness in arms and legs, gastrointestial problems, and you can't tell the difference between hot and cold. 
- Queen AngelfishPhotos By Casey Patton and Cathleen Bester. Florida Museum of Natural History.
- Queen Angelfish National Geographic Society.
- Queen angelfish MarineBIO.org.
- Queen Angelfish Fishlore.com.
- Queen Angelfish By David Brough. CFS. Animal-World.