An adult blue angelfish is blue-brown in color with green hues and bright yellow on the tip of its tail and fins. Their young, however, have a completely different coloration. A young blue angelfish is dark blue with a yellow tail and some yellow on its fins. It also has vertical blue bars on its body. As it ages, the bars fade away and the body color becomes lighter and some browns and greens are added.
The blue angelfish can grow up to 18 inches in length. It has a large mouth and comb-like teeth. It is often collected for aquariums. This fish occasionally breeds with the queen angelfish, which is very similar to it. This hybrid is called the townsend angelfish. An adult blue angelfish can produce a loud thumping sound that warns predators and also startles divers.
It is found in the western Atlantic part of from Bermuda, the Bahamas and Florida to the Gulf of Mexico, and also to Yucatan, Mexico. The blue angelfish tends to stay near rocks, coral, and sponges at depths of between 6½ and 300 feet (2-92 m). It also lives around boulders, in caves, and crevices in shallow water. Young blue angelfish tend to live in bays and channels.
The blue angelfish can live up to 20 years.