Rockmover Wrasse, Novaculichthys taeniourus
Rockmover Wrasse, Novaculichthys taeniourus, Juveniles. Underwater photographs taken in Zihuantanejo Bay, Guerrero, November 2021. Photographs courtesy of Maude Jette, Dive Zihuantanejo, www.Divezihuantanejo.com.
Rockmover Wrasse, Novaculichthys taeniourus, Juvenile. Underwater photograph taken in coastal waters off Kailua-Kona, Hawaii, April 2015. Photograph courtesy of Bob Hillis, Ivins, Utah.
Rockmover Wrasse, Novaculichthys taeniourus, Juveniles. Underwater photographs taken in Zihuantanejo Bay, Guerrero, March 2018. Photographs courtesy of Ron Woheau, Zihuantanejo.
Rockmover Wrasse, Novaculichthys taeniourus. Underwater photograph taken in coastal waters off Kailua-Kona, Hawaii, February 2015. Length: 23.0 cm (9.0 inches). Photograph courtesy of Bob Hillis, Ivins, Utah.
Rockmover Wrasse, Novaculichthys taeniourus. Underwater photograph taken in Zihuantanejo Bay, Guerrero, March 2018. Photograph courtesy of Ron Woheau, Zihuantanejo.
The Rockmover Wrasse, Novaculichthys taeniourus, is a member of the Wrasse or Labridae Family, and is known in Mexico as cuchillo dragón. Their common name is derived from their behavior of turning over rocks seeking prey. Juveniles are known as the Dragon Wrasse. The Rockmover Wrasse is a truly gorgeous fish. Globally, there are four species in the genus Novaculichthys, of which one is found in Mexican waters of the Pacific, this species.
The Rockmover Wrasse has an elongated, oblong, and very compressed body. Juveniles (IP) are mottled with green, red or brown bands and are covered with white spots; they have brown lines radiating from their eyes and a pink belly. Adults (TP) are greenish-brown with a white spot on each side of their head; their anal and dorsal fins are black and their caudal fin is black with a white base. They lack the radiating lines from the eyes and the pink belly found in juveniles and have a yellow spot at the base of their pectoral fin. Their head is off-white and wedged-shaped. They have medium-sized eyes set high on their head and a mid-sized terminal mouth that opens in the front. They have 2 pairs of short canines at the front of their upper and lower jaws. Their anal fin has 3 spines and 12 or 13 rays; and, their dorsal fin has 9 spines, with the first 2 spines being greatly elongated in juveniles, and 12 or 13 rays. They do not have scales on their heads. Their lateral line is broken into two parts.
The Rockmover Wrasse is a benthopelagic species found in shallow semi-exposed reef flats, in lagoons, and in seaward reefs in waters between 24oC (75oF) and 28oC (83oF) at depths between 14 m (45 feet) and 24 m (80 feet). They reach a maximum of 30 cm (12 inches) in length. They prefer hard-bottomed grassy areas of mixed sand and rubble exposed to mild surge and will reside in sand at night. Juveniles are found in shallow areas on rubble among large patch reefs and will mimic floating algae. They travel in pairs feeding on benthic invertebrates including brittle stars, crabs, mollusks, polychaete worms, and sea urchins, often working to dislodge food. They are highly territorial. They have the ability to quickly submerge themselves in sand as a defense mechanism. Reproduction is poorly understood but is believed to occur via protogynous sequential hermaphroditism with individuals beginning life as either male or female and females changing to males later in life. They are oviparous with broadcasted eggs that are fertilized externally. Eggs and larvae are pelagic. The Rockmover Wrasse is poorly studied with very limited information available about their lifestyle and behavioral patterns including specific details on age, growth, longevity, movement patterns, diet, habitat use, and reproduction.
The Rockmover Wrasse has a wide distribution in the tropical Indian and Pacific Oceans. In Mexico they have a limited distribution and are found from La Paz to Cabo San Lucas along the east coast of Baja and from the Central Gulf southward to Guatemala along the west coast of the mainland.
The Rockmover Wrasse is straightforward to identify and cannot be confused with any other species.
From a conservation perspective the Rockmover Wrasse is currently considered to be of Least Concern with stable, widely distributed populations. They are prone to coral reef destruction and local endangerment. The Rockmover Wrasse is a popular aquarium fish due to their beautiful coloration and hardiness, however, they are semi-aggressive and require large tanks and moderate care. They are also known as escape artists. They are utilized as a human food are sold fresh on a limited basis and retained by subsistence fishermen.