Rock Wrasse, Halichoeres semicinctus: The Rock Wrasse varies in color from yellowish brown to greenish in adults and from brown to bright green in juveniles.
Large terminal males have a prominent dark bar behind the pectoral fin that extends ventrally from the top edge of the eyes to near the pelvic fin base. The females have faith bars (as pictured below). The juveniles have a dark ocellus (circular spot) near the beginning of the soft dorsal fin and a white mid-lateral stripe.
A key to identification of the Rock Wrasse are the large forward pointing teeth found in the front part of the mouth.
The Rock Wrasse has 12 dorsal soft rays, large scales, and a square caudal fin. The Rock Wrasse reaches a maximum length of 15 inches, with the sex change from female to male occurring at about 12 inches. It is found close to rocks near patches of sand and in tidal pools within the first 80 feet of the water column.
At night this fish species sleeps half-buried in sand with its head protruding and has been found stranded on some occasions in the early morning by overnight very low tides. During the day the Rock Wrasse forages for small invertebrates.
The Rock Wrasse is most likely confused with the Chameleon Wrasse, Halichoeres dispilus (unique coloration pattern) and the Red Shouldered Wrasse, Stethojulis bandanensis (small teeth; thin blue stripes on head and upper back).
In Mexican fishing waters the Rock Wrasse is found along the Pacific Coast of the Baja California peninsula south to Magdalena Bay and in the upper two-thirds of the Sea of Cortez.
The Rock Wrasse is a member of the Labridae or Wrasse Family which are known in Mexico as Doncellas and Señoritas.