Fish Identification Photos: Purple Surgeonfish, Yellowfin Surgeonfish, Acanthurus xanthopterus: The Purple Surgeonfish has pale blue sides, with many irregular dark lines, and a horizontal yellow band in front of and passing around the eye. Upon collection the Purple Surgeonfish quickly changes to a uniform dark purple-gray. The Purple Surgeonfish also has a white or tan bar at the base of the caudal fin, and the outer third of the pectoral fins is yellow. This coloration patent makes the Purple Surgeonfish a very easy species to identify, keeping in mind that the Purple Surgeonfish is very similar in size and shape to the Achilles Tang, Achilles Achilles; the Convict Tang, Acanthurus triostegus triostegus; and the Whitecheek Surgeonfish, Acanthurus nigricans.

The Purple Surgeonfish is the largest member of the Acamtjirodae or Sugeonfish Family known in Mexico as Peces Cirujanos. The Surgeonfish are reef fishes with small mouths that are easily recognized by the presence of a single forward-directed collapsible lancet-like spine on each side of the caudal peduncle.

This spine renders these fish as “very dangerous” to handle as the spine can inflict deep slashing wounds providing the species with a unique defense mechanism. Surgeonfish are primarily herbivorous fishes grazing on algae found on rocks. Globally, 72 species have been identified of which only 5 live in the Sea of Cortez.

The Purple Surgeonfish is fairly abundant, reaching 26 inches in length and up to 7 pounds, but is exceedingly difficult to catch. When hooked the Purple Surgeonfish makes a fierce foe, especially on light tackle. The Purple Surgeonfish can be found over sandy areas adjacent to rocky reefs at depths up to 300 feet in the water column.

In Mexico, the Purple Surgeonfish is found only in the most southern portion of the Sea of Cortez between La Paz and Cabo San Lucas, Baja California Sur, and along the coast of the mainland from Acapulco south to Guatemala. The Purple Surgeonfish is absent from all oceanic islands. It is considered a good food fish. However, there is a concern that it may contain ciguatoxin, poisonous to humans when eaten, present in surgeonfish found outside the Eastern Pacific.

Note: the Scientific Community believes that Acanthurus crestonis, reported to be present in the Mazatlan area, is the same species.

Purple Surgeonfish, Yellowfin Surgeonfish, Acanthurus xanthopterus: Caught with Capt. Pata in the panga Salome, La Playita, San Jose del Cabo, Baja California Sur, Mexico, late morning in May 2003, in 77-degree water, near the surface, in 100 to 150-foot deep water, utilizing a flylined anchovy pinned on a Mustad 92553 hook, size #4, or on cut bonito with an 0.5-ounce weight, 25 miles north of La Playita. Size approximately 16 inches and five pounds and was a true warrior. A rather rare catch that is viewed by locals as good table fare. This is a tricky fish to catch, with a school of 20 to 30 brought to the surface by slow sinking chum and then presenting similar bait with the correct hook size (small). Turns from distinctly patterned glamorous purple to black within five minutes. Should be handled with extreme care since it has a pair of scalpels located on the port and starboard sides of the tail section. Description and photo courtesy John Snow. Purple Surgeonfish, Yellowfin Surgeonfish, Acanthurus xanthopterus: In July of 2003, my trip was with Eric Brictson, Gordo Banks Pangas, San Jose del Cabo, Baja California Sur, Mexico. Captain Tony and I fished the rocks and reefs north of La Playita. Description and photo courtesy Jack Simpson.