A small fast-swimming wrasse of shallow rock, the male carrying a red spot behind the pectoral fin.
To 15 cm, with females to about 8. The initial phase is grey-brown with a thin white line along the head below the eye, fine white spotting on the upper sides, and a red blotch immediately above the pectoral fin base. Terminal males are blue-green to yellow-brown above with the same red patch and four thin blue stripes on the head.
The red shoulder patch is the whole identification. It is the only Stethojulis in the tropical eastern Pacific, and no eastern Pacific Halichoeres or Thalassoma carries that mark.
Nought to fifteen metres over shallow mixed sand, rubble and rock, usually alone or in small groups and constantly moving. It eats small planktonic and benthic crustaceans.
It is an Indo-Pacific fish with a foothold in the eastern Pacific: Cocos, Malpelo, Clipperton, the Galapagos and the Gulf of California, reaching Baja in El Niño years.
Ratings are per location: 1 means found on most dives that look for it, 5 means a handful of records. Where enough dives have been logged the figure is calculated from them; otherwise it is an editorial estimate, and says so. We publish habitat and destination, not the dive site.