Sabertooth Blenny, Plagiotremus azaleus

Sabertooth Blenny, Plagiotremus azaleus, Juvenile. Fish collected in the open ocean with a bait net, March 2010. Length: 5.1 cm (2.0 inches). Identification courtesy of Dr. Ross Robertson, Smithsonian Tropical Research Institute, Panama and reconfirmed by H.J. Walker, Scripps Institution of Oceanography, La Jolla, California.

Sabertooth Blenny, Plagiotremus azaleus. Fish provided by the commercial fishermen of the greater Los Cabos area, Baja California Sur, March 2011. Length: 4.5 cm (1.8 inches). Identification courtesy of Dr. Phil Hastings, Scripps Institution of Oceanography, La Jolla, California.

Sabertooth Blenny, Plagiotremus azaleus. Underwater photograph taken in coastal waters off Kailua-Kona, Hawaii, August 2014. Photograph courtesy of Bob Hillis, Ivins, Utah.

Sabertooth Blenny, Plagiotremus azaleus. Underwater photographs taken in coastal waters of the greater Los Cabos area, Baja California Sur, May 2018. Photographs courtesy of Bob Hillis, Ivins, Utah.

Sabertooth Blenny, Plagiotremus azaleus. Underwater photographs taken in Zihuantanejo Bay, Guerrero, February 2019 and February 2023. Photograph courtesy of Ron Woheau, Zihuantanejo.

Sabertooth Blenny mimicking a Juvenile Cortez Rainbow Wrasse, Thalassoma lucasanum. Underwater photograph taken in Zihuantanejo Bay, Guerrero, February 2023. Photograph courtesy of Ron Woheau, Zihuantanejo.

The Sabertooth Blenny, Plagiotremus azaleus, is a member of the Combtooth Blenny or Blennidae Family, and is known in Mexico as diente sable. Globally, there are ten species in the genus Plagiotremus, of which one, this species, is found in Mexican waters of the Pacific Ocean.

The Sabertooth Blenny has a very elongated slender body. They have a broad brown mid-lateral band that runs from the snout, through the eye, to the caudal fin mid-body with a narrow off-white stripe immediately above. Their dorsal fin is black with a blue-white outer margin. They are off-white ventrally. Their head has a long conical protruding snout and a small inferior mouth with a large canine tooth projecting from each side of the lower front jaw and used for protection. Their anal fin base is low and long with 2 spines and 27 to 30 rays and 4 equally spaced black spots along its base; their caudal is concave with a long filament in the center; and their dorsal fin is low with a long base and 12 to 14 spines and 31 to 35 rays and originates before the small gill openings. Their skin is smooth and without scales and they do not have a lateral line.

The Sabertooth Blenny is a non-migratory coastal demersal species found in very shallow waters and in weed-covered intertidal and sub-tidal rocky areas (including tidal pools) at depths up to 26 m (85 feet). They reach a maximum length of 10.2 cm (4.0 inches). They are highly territorial and will vigorously defend their habitat against intruders. They are known to inhabit empty tube-worm shells and to extend their heads from the opening. They are diurnal leaving their shelter to feed by relying on mimicry; they become darker and join schools of Cortez Rainbow Wrasse, Thalassoma lucasanum at levels of less than 1 per 100 for disguise to obtain potential access to prey fishes and to avoid predation or they hunt in packs of up to 100 individuals and attack larger fish such as Pacific Dog Snapper, Lutjanus novenfasciatus  and Leopard Grouper, Mycteroperca rosacea. They primarily consume the skin of larger fish and eggs of a wide variety of species attached to the substrate. Reproduction is oviparous in distinct pairs with the females depositing eggs in protected areas. The eggs are sticky and adhere to the walls of the shelter; they are then fertilized by the males who guard them for 2 to 3 weeks until they hatch. The Sabertooth Blenny is a small shallow-water species this 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 Sabertooth Blenny is a resident of all Mexican waters of the Pacific Ocean with the exception that they are absent from the extreme northern portions of the Sea of Cortez.

The Sabertooth Blenny is fairly easy to identify and cannot be confused with any other species due to its unique coloration patterns and large saber like tooth.

From a conservation perspective the Sabertooth Blenny is currently considered to be of Least Concern with stable, widely distributed populations. They are too small in stature to be of interest to most and are normally a “catch-and-release.” They are known to nip at divers but overall are considered harmless to humans.