Barberfish, Johnrandallia nigrirostris

Barberfish, Johnrandallia nigrirostris. Fish provided by the commercial fishermen of the greater Los Cabos area, Baja California Sur, December 2011. Length: 6.2 cm (2.4 inches).

Barberfish, Johnrandallia nigrirostris. Underwater photographs taken in coastal waters off Puerto Vallarta, Jalisco, September 2021 and July 2023. Photograph courtesy of Kevin Erwin, Seattle, Washington.

Barberfish, Johnrandallia nigrirostris. Underwater photograph taken in coastal waters off Buena Vista, Baja California Sur, June 2017. Photograph courtesy of Bob Hillis, Ivins, Utah.

Barberfish, Johnrandallia nigrirostris. Underwater photograph taken in coastal waters off Los Cabos, Baja California Sur, June 2017. Photograph courtesy of Bob Hillis, Ivins, Utah.

Barberfish, Johnrandallia nigrirostris. Underwater photographs taken in Zihuantanejo Bay, Guerrero, March 2018. Photographs courtesy of Ron Woheau, Zihuantanejo.

Barberfish, Johnrandallia nigrirostris. Underwater photographs taken in Zihuantanejo Bay, Guerrero, November 2018. Photographs courtesy of Maude Jette, Dive Zihuantanejo,  www.Divezihuatanejo.com.

Barberfish, Johnrandallia nigrirostris.  Underwater photograph taken in coastal waters off Loreto, Baja California Sur, October 2024. Photograph courtesy of Bob Hillis, Ivins, Utah.

The Barberfish, Johnrandallia nigrirostris, is a member of the Butterflyfish or Chaetodontidae Family, and is known in Mexico as mariposa barbero. The Butterflyfish are reef fish and some of the most colorful tropical fish in the ocean. Globally there are ninty-three species of Butterflyfish in the genus Chaetodon, of which five are found in Mexican waters, four in the Atlantic and one in the Pacific Ocean.

The Barberfish has a body that is a strongly compressed oval disc with a depth that is 66% to 70% of standard length. They are overall yellow in color with a whitish head and black bands on their snout, across their eyes and forehead, and along the base of their dorsal fin. They also have black areas around their eyes, on the edge of their gill cover, and on the base of their pectoral fins. Their head has a short pointed snout with a small terminal mouth that is equipped with long and slender teeth. Their anal fin has 3 spines and 18 to 20 rays with the second spine being longer than the third and a rounded margin; their caudal fin is straight; and their dorsal fin has 12 spines, the fourth of which is the longest after which the spine length gradually decreases; and, their second dorsal fin has 24 or 25 rays and has a rounded margin. Their body is covered with large rough scales. Their lateral line is complete.

The Barberfish is found in small to very large schools within reefs at depths up to 40 m (130 feet). They reach a maximum of 20.0 cm (7.9 inches) in length. They are grazers and pickers and consume small organisms including algae, gastropods, and small crustaceans. Their mode of feeding predisposes them to be cleaners, which pick parasites from other fish such as the Pacific Creolefish, Paranthias colonus. The Barberfish is poorly studied with very limited information available about their lifestyle and behavioral patterns including specific details on age, growth, longevity, movement patterns, diet, habitat use, and reproduction.

The Barberfish is a resident of all Mexican waters of the Pacific with the exception that they are absent from Guerrero Negro, Baja California, northward along the central and northwest coasts of the Baja.

The Barberfish is most likely confused with the Scythe Butterflyfish, Prognathodes falcifer (inverted black “V” upper body) and the Threebanded Butterflyfish, Chaetodon humeralis (two wide vertical black bars originating from anterior and posterior first dorsal fin).

From a conservation perspective the Barberfish is currently considered to be of Least Concern with stable widely distributed populations. They are sold commercially for the aquarium trade and are also of interest to divers.