Redside Blenny

Redside Blenny, Malacoctenus hubbsi

The Redside Blenny, Malacoctenu hubbsi, whose common Spanish name is trambollo rojo, is a species in the Labrisomid Blenny or Labrisomidae Family, known as trambollos in Mexico. Globally, there are 18 species in the genus Malacoctenus, fourteen of which are found in Mexican waters, six in the Atlantic and eight in the Pacific.

The Redside Blennies have shortened elongated bodies with a uniform depth throughout that tapers gradually at the rear into the tail. The sexes have different colorations. Males are light green to reddish-brown dorsally and reddish to pinkish ventrally with five or six irregular shaped dark brown bars on their sides and narrow stripes below. Females are similarly colored but lack the reddish and pink colorations ventrally and have spotted caudal and dorsal fins. Both sexes have bars and spotting in their throat area and a dark spot in front of their pectoral fin base. Their head is slender with a pointed snout, large eyes, and a pair of closely set and heavily branched cirri. They have a branched cirrus over each eye. 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 two spines and 18 to 23 rays; their caudal fin is square; and their dorsal fin has 19 to 21 spines and 9 to 13 rays with a slight notch in between. They have 11 or 12 gill rakers. They are covered with a limited number of scales. A key to identification is the lack of scales on the midline in front of the dorsal fin.

The Redside Blennies are a shallow water coastal species found in intertidal shallows, bays, and estuaries in rocky areas at depths up to 65 feet. They reach a maximum length of 9.0 cm (3.5 inches). 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 Redside Blennies are are poorly studied and very little is known about their behavioral patterns.

In Mexican waters the Redside Blennies are found from Guerrero Negro southward along the soutwest coast of Baja and throughout the Sea of Cortez; they are absent from along the coast of the mainland south to Guatemala.

The Redside Blenny can be confused with the Fishgod Blenny, Malacoctenus ebisui (numerous white spots on throat), the Mexican Blenny, Malacoctenus mexianus (dark oval with white margins on gill cover), the Sonora Blenny, Malacoctenus gigas (red lines on lower body), the Throatspotted Blenny, Malacoctenus tetranemus (many dark spots on throat) and the Zaca Blenny, Malacoctenus zacae (brown lines on lower body).

The Redside Blennies are too small to be of interest to most and are normally a “catch-and-release.”

Redside Blenny, Malacoctenus hubbsi, female. Fish provided by the commercial fishermen of Puerto Los Cabos, Baja California Sur, January 2008. Length: 2.5 cm (1.0 inch). Fish identification courtesy of H.J. Walker, Jr., Scripps Institution of Oceanography, La Jolla, CA.