Yellowtail surgeonfish in Los Cabos

How to recognize it

Oval, compressed body with a steep head profile, an eye set high on the head and a small mouth low on the head. Gray with a bright yellow tail fin, a dark bar through the eye and another through the shoulder, and three bony knobs along each side of the tail base, with black spots there. Fish in the Gulf of California are usually covered in small black spots (the form once called P. punctatus); farther south many are plain gray, and some have faint spots on only part of the body. Small juveniles are mainly yellow.

Biology

The yellowtail surgeonfish lives only in the tropical eastern Pacific, from the Gulf of California to Peru. Spotted and plain fish occur throughout that range, but the spotted form is more common in the north, so it is the one you usually see in Cabo. It lives on rocky reefs from the surface to 65 m and often travels in large schools.

It is a herbivore that grazes algae off rocks and coral. For more than 150 years the spotted and plain fish were treated as two species. A 2019 study compared museum specimens, a mitochondrial gene and more than 800 nuclear DNA regions from fish collected in Baja California, Costa Rica and Panama. Counts and measurements overlapped completely, both forms shared one main mitochondrial type and no fixed genetic differences turned up, so the spotted P. punctatus was merged into P. laticlavius.

Seeing them from the boat

The yellowtail surgeonfish is a fish for snorkelers and divers, not a sport fish. Look for schools of gray, spotted fish with bright yellow tails grazing over rocky reefs in shallow water.

It eats algae, so it seldom takes baits or lures. If one is hooked by accident, handle it carefully around the hard bony knobs on the tail base and release it. Sport fishing is not allowed inside Cabo Pulmo National Park.

Rules & conservation

Not a sport fish. Handle with care around the tail base and release it.

Don't confuse it with

The yellowfin surgeonfish (Acanthurus xanthopterus) is purplish gray to brown with a yellowish outer pectoral fin and yellow around the eye, has no yellow tail and carries a single folding spine at the tail base. The goldrim surgeonfish (Acanthurus nigricans) is black with a white blotch below the eye and a white tail. A gray fish with a bright yellow tail and three fixed bony knobs on the tail base is the yellowtail surgeonfish.

Questions

By Max VargasTop Anglers, Cabo San Lucas · international judge at big game fishing world championships · reviewed October 2026

Sources

• Smithsonian Shorefishes of the Eastern Pacific: Prionurus laticlavius
• FishBase: Prionurus laticlavius
• FishBase: Prionurus punctatus (synonym note)
• Ludt et al. 2019, species limits in Tropical Eastern Pacific Prionurus (Ecology and Evolution)
• Reef Life Survey: Prionurus laticlavius
• Florent's Guide to the Eastern Pacific Reefs: yellowtail surgeonfish (Cabo San Lucas photos)
• The ETYFish Project: Acanthuridae etymology
• Smithsonian Shorefishes of the Eastern Pacific: yellowfin surgeonfish
• Smithsonian Shorefishes of the Eastern Pacific: goldrim surgeonfish
• NOM-059-SEMARNAT-2010, 2019 annex (DOF)
• NOM-017-PESC-1994, 2013 amendment (DOF)

Top illustration: Top Anglers. Photos: iNaturalist contributors, credited on each photo.