King Angelfish, Holacanthus passer: The adult King Angelfish has a dark blue gray coloration with one narrow vertical white band behind the gill covers. The King Angelfish has yellow-orange caudal and pectoral fins. In stark contrast, juvenile King Angelfish are multicolored, with a series of vertical stripes, yellow, narrow blue, brown through the eye, narrow blue, broad orange, white, and then five dark brown separated by narrow blue lines.
The body of the King Angelfish has a narrow circular blue line. These markings make the King Angelfish a very easy species to identify, with the possible exceptions being the Clarion Anglefish, Holacanthus clarionensis (only found at the Revillagigedo Islands and Cabo Pulmo and is a bright yellow orange with is blue and brown aft of the gill covers with yellow pelvic fins; the juveniles are quite similar to the King Angelfish with the exception that the blue markings are black); and the Cortez Angelfish, Pomacanthus zonipectus (vertical stripes that are broad yellow, black, yellow, black, broad grey and black and a pale caudal fin).
The King Angelfish is abundant but only in certain parts of the Sea of Cortez, and it reaches 18 inches in length. The King Angelfish can be found in an around rocky coral reefs at depths up to 200 feet in the water column. It feeds primarily on plankton and sponges. In Mexican fishing waters , the King Anglefish is found only in the lower two-thirds of the Sea of Cortez, and along the coast of the mainland south to Guatemala. The King Angelfish appears to be absent from around the oceanic islands. The King Anglefish is of most interest to scuba divers and is of virtually no interest as a sport fish.
The King Angelfish is a member of the Pomacanthidae or Angelfish Family, known in Mexico as Peces Ángel. The Angelfish are reef fishes that are among the most colorful tropical reef fishes in the world. They are characterized by a strong conspicuous stout spine originating at the lower cheek. Young angelfish undergo radical coloration changes as they mature. They are grazers and pickers that consume small organisms including slow-moving algae, coral polyps, hydroids, sponges, tunicates and worms. Their mode of feeding predisposes them to be cleaners, which pick parasites from other fishes. Globally, 74 species of Angelfish have been identified of which only three live in the Sea of Cortez.