Mexican Triplefin, Enneanectes macrops

Mexican Triplefin, Ennenectes macrops, Females. An exceptional portfolio of underwater photographs taken in Zihuantanejo Bay, Guerrero, March 2022 and December 2022. Photographs and identifications courtesy of Ron Woheau, Zihuantanejo.

Mexican Triplefin, Ennenectes macrops, Males. An exceptional portfolio of underwater photographs taken in Zihuantanejo Bay, Guerrero, March 2022. Photographs and identifications courtesy of Ron Woheau, Zihuantanejo.

The Mexican Triplefin, Enneanectes macrops, is a member of the Triplefin or Tripterygiidae Family, and are known in Mexico as tres aletas mejicana. Its common name stems from the division of its dorsal fin into three parts, two of which have spines. Globally, there are one hundred forty-five members in the Tripterygiidae Family placed into thirty genera with ten known species in the genus Ennenectes of which eight are found in Mexican waters, three in the Atlantic and five in the Pacific Ocean.

The Mexican Triplefin has a robust body. They are a mottled red and brown color with the body covered with scales with brown margins that form a meshwork pattern. They have four irregular dark bars on the body and one on the base of the tail. Their head has two dark bars under the eye and other on the gill covers. The anal and dorsal fins have dark diagonal dark bars, the top of the caudal base is white, the caudal fin is dark with a clear central bar, and the pectoral fins have a dark base with alternating dark and yellow bars. Their head is broad with large eyes set high on the head with well-developed cirrus over the eyes with small close-set spines on top of the head behind the eyes. Their anal fin has 16 to 18 rays; their first dorsal fin has 3 spines; their second dorsal fin has 11 or 12 spines and 8 to 10 rays; their third dorsal fin has 4 to 10 rays; their pectoral fins have 14 to 16 rays; and, their pelvic fins have 1 spine and 2 rays. They are covered with large rough scales. Their lateral line is straight and broken into two portions.

The Mexican Triplefin is found in shallow water reef environments around rocks and boulders at depths up to 15 m (50 feet). They reach a maximum of 5.0 cm (2.0 inches) in length. They consume small invertebrates. Reproduction is oviparous with hemispherical eggs that attach themselves to the substrate via sticky threads. The larvae are planktonic. The Mexican Triplefin 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 Mexican Triplefin can be confused with the Delicate Triplefin, Enneanectes carminalis (dark bar under their eyes), and the Slender Triplefin, Enneanectes glendae (head with red spots; body with orange blotches and bars).

The Mexican Triplefin is a resident of Mexican waters of the Pacific Ocean but has a limited distribution being found from along the coast of the mainland from Sinaloa south to Guerrero.

From a conservation perspective the Mexican Triplefin has not been formally evaluated. They are seldom seen by humans and are of limited interest to most.