Cortez rainbow wrasse in Los Cabos

How to recognize it

Slender, elongate and compressed, with a concave tail and a scaleless head. Most fish are in the initial phase: a broad dark brown to greenish stripe runs from the snout through the eye and along the body, bordered by a bright yellow stripe and a red stripe. Terminal-phase males look like a different fish: a bluish head with darker blue-green stripes below the eye, a broad yellow bar just behind the head, a purplish body, a bluish tail and a yellow pectoral fin with a blue edge. It reaches only 15 cm (6 in).

Biology

The Cortez rainbow wrasse lives only in the eastern Pacific, from central Baja and the central Gulf of California to central Peru, including all the offshore islands except Clipperton. It is a resident of rocky and coral reefs from the surface to 64 m, usually between 2 and 25 m. The first specimens described, in 1862, came from Cabo San Lucas.

It forms aggregations that feed on plankton over the reef, and also eats small bottom crustaceans and fish eggs. Young fish sometimes clean parasites off other fish. Like many wrasses it is a protogynous hermaphrodite: fish start life as females, and the largest can turn into terminal-phase males, a change completed in 2 to 6 weeks. Striped fish spawn in loose groups that rise toward the surface to release eggs and sperm, while terminal males spawn with females one at a time.

Seeing them from the boat

The Cortez rainbow wrasse is a fish for snorkelers and divers, not anglers. Look for loose schools of striped fish over rocky reefs in shallow water; the blue-headed males are bigger and fewer. It is not a sport fish and is not used for food.

At 15 cm (6 in) with a small mouth, it is too small to target on sport tackle. If one ever comes up on a small bait, unhook it gently and let it go. Sport fishing is not allowed inside Cabo Pulmo National Park.

Rules & conservation

Not a sport fish. Best seen while snorkeling Cabo's rocky reefs.

Don't confuse it with

The sunset wrasse (Thalassoma grammaticum) grows to 32 cm. Its terminal males are green to blue with a pinkish head crossed by narrow green bands and a dark band on the pectoral fin, and they have no yellow collar; its initial phase is plain greenish yellow, not striped yellow, red and brown. Only the Cortez rainbow wrasse male has a broad yellow bar right behind a blue head.

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: Thalassoma lucasanum
• FishBase: Thalassoma lucasanum
• Reef Life Survey: Cortez rainbow wrasse
• Florent's Guide to the Eastern Pacific Reefs: Cortez rainbow wrasse (Cabo San Lucas photos)
• The ETYFish Project: Labridae etymology
• San Diego Natural History Museum, Ocean Oasis field guide: Cortez rainbow wrasse
• McCauley et al. 2008, aquarium trade and Thalassoma lucasanum in Costa Rica (Ciencias Marinas)
• Smithsonian Shorefishes of the Eastern Pacific: sunset wrasse
• NOM-059-SEMARNAT-2010, 2019 annex (DOF)

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