Throatspotted Blenny, Malacoctenus tetranemus

Throatspotted Blenny, Malacoctenus tetranemus. Fish caught from coastal waters off Mazatlán, Sinaloa, October 2021. Length: 12.5 cm (4.9 inches). Catch, photograph and identification courtesy of Bart, The Netherlands  (worldangler.eu).

Throatspotted Blenny, Malacoctenus tetranemus, Females. Underwater photographs taken in Zihuantanejo Bay, Guerrero, during in 2018, 2019 and 2022. Photographs and identifications courtesy of Ron Woheau, Zihuantanejo.

Throatspotted Blenny, Malacoctenus tetranemus, Males and Breeding Males. Underwater photographs taken in Zihuantanejo Bay, Guerrero, during calendar 2018 and 2019. Photographs and identifications courtesy of Ron Woheau, Zihuantanejo.

Throatspotted Blenny, Malacoctenus tetranemus. Underwater  photo taken in the greater Los Cabos area, Baja California Sur, October 2019. Photograph courtesy of Bob Hillis, Ivins, Utah.

The Throatspotted Blenny, Malacoctenus tetranenus, is a member of the Labrisomid Blennies or Labrisomidae Family, and is known in Mexico as trambollo pintado. Globally, there are eighteen species in the genus Malacoctenus, of which fourteen are found in Mexican waters, six in the Atlantic and eight in the Pacific Ocean.

The Throatspotted Blenny has a shortened elongated body with a uniform depth throughout that tapers gradually at the rear into the tail. The sexes have similar coloration being dark brown dorsally and tan ventrally. They have a double row of dark greenish-brown blotches on their sides and their lower body has numerous dark spots. They also have a distinctive line that extends from the tip of their snout through the eye to the mid-body (pictured below). Their throat is densely covered with small dark spots after which they are named. They have a pair of black spots just behind the upper half of the eyes and just behind the lower half of the their eyes, a key to the identification. Their head is slender with a pointed snout, large eyes, a branched cirrus over each eye, and a pair of closely set and heavily branched cirri. Their mouth is small, opens at the front, and is equipped with one row of large teeth on the upper jaw. Their anal fin has 2 spines and 18 to 20 rays; their caudal fin is square; and, their dorsal fin has 18 to 20 spines and 9 to 12 rays with a slight notch in between. They have 11 to 15 gill rakers. They are covered with small scales.

The Throatspotted Blenny is a small shallow water coastal species found at depths up to 26 m  (85 feet). They reach a maximum of 7.5 cm (3.0 inches) in length. They are diurnal highly territorial predators that feed mostly on benthic crustaceans including small crabs. Reproduction is oviparous with females depositing eggs in protected areas. The Throatspotted Blenny 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 Throatspotted Blenny is a resident of Mexican waters of the Pacific Ocean but has a limited range being found throughout the Sea of Cortez and along the coast of the mainland south to Guatemala; they are absent from the entire west coast of Baja.

The Due to o dark spots behind their eyes the Throatspotted Blenny is easily confused with Fishgod Blenny, Malacoctenus ebisui(lack the two dark spots behind the eyes; have very short tuffed circus over eyes).

From a conservation perspective the Throatspotted Blenny has not been formally evaluated. They are small in stature and of limited interest to most.