Mimic Blenny, Gobioclinus guppyi

Mimic Blenny, Gobioclinus guppyi. Fish caught from coastal waters off Noord, Aruba, February 2023. Length: 8.1 cm (3.2 inches). Catch, photograph, and identification courtesy of James Lafontaine, Long Island, New York.

The Mimic Blenny, Gobioclinus guppyi, is a member of the Labrisomid Blenny or Labrisomidae Family, and is known in Mexico as sapito prieto and trambollo mimico. Globally, there are seven species in the genus Gobioclinus, of which five are found in Mexican waters with all five in the Atlantic Ocean.

The Mimic Blenny have a robust body with a broad head that has a blunt snout, a large eye with a branched cirrus over each eye and two cirri on each side of the nape, a large mouth that is slightly oblique equipped with small teeth located behind an outer row of larger teeth and present on the sides of the roof of the mouth. They are brown in color with a greenish cast with five brown to purplish black bars that extend on the anal and dorsal fins. The darker areas are covered with small white spots. The base of the dorsal fin has a narrow dark bar. The females have pail green fins and are heavily spotted; males have red fins with a few spots and during breeding can be a uniform black color. They have a well-developed ocellus on the gill cover. Their anal fin has 2 spines and 18 or 19 rays; their caudal fin is rounded; their dorsal fin has 18 or 19 spines and 9 to 12 rays; their short pelvic fins have 1 spine and 3 rays and are inserted before the pectoral fins, and the pectoral fins have 13 rays. They have 13 to 14 gill rakers. The lateral line is visible in the front half of the body. The rear half of the body are covered with smooth scales.

The Mimic Blenny are a shallow water coastal species found within rocky and rubble shores within algal mats, reefs, seagrass beds and tidal pools at depths up to 8 m (25 feet). They reach a maximum of 10.8 cm (4.3 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 Mimic 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 Mimic Blenny is a resident of Mexican waters of the Atlantic Ocean and if found in the Gulf of Mexico from Tuxpan, Veracruz south and east to the Yucatan Peninsula and along the east coast of the Yucatán Peninsula in the Caribbean south to Belize.

The Mimic Blenny can be easily confused with a series of other Labrisomid Blennies including the Longfin Blenny, Gobioclinus haitiensis, the Palehead Blenny, Gobioclinus gobio, the Puffcheek Blenny, Gobioclinus bucciferus, and the Whitecheek Blenny, Brockius albigenys, all of which lack an ocellus on the gill cover and the Quillback Blenny, Gobioclinus filamentous (large dark black ocellus).

From a conservation perspective the Mimic Blenny is currently considered to be of Least Concern with stable, widely distributed populations. They are small in stature and of limited interest to most.