Mexican Barnacle Blenny, Acanthemblemaria macrospilus
Mexican Barnacle Blenny, Acanthemblemaria macrospilus. Underwater photographs taken in Zihuantanejo Bay, Guerrero, from December 2018 to March 2019. Photographs courtesy of Ron Woheau, Zihuantanejo.
The Mexican Barnacle Blenny, Acanthemblemaria macrospilus, is a member of the Tube Blenny or Chaenopsidae Family, that is known in Mexico as known tubícola mexicano. Globally, there are twenty species in the genus Acanthemblemaria, six of which are found in Mexican waters, two in the Atlantic and four in the Pacific Ocean.
The Mexican Barnacle Blenny has an elongated body. They are wildly colored: their body is tan; their head is grayish-brown and covered with small pale blue spots; the iris of their eyes is normally red above and black below with a thin cream-colored inner ring; they have black blotches under their eyes, at the rear of their cheeks, and at the rear of their gill covers; and their lower jaw transitions from creamy white at the tip, red in the middle, and black on the throat. They have a mid-lateral row of large black spots and dark brown saddles along the base of their dorsal fin. Their dorsal fin is red at the front with a round black spot at the base of the first two spines. Their head is long and blunt with short pointed head spines set in a diamond-shaped patch after and between the eyes. They have one pair of cirri over their eyes and cirri on their nostrils. They have two rows of well-developed teeth on the side of the roof of their mouth. Their anal fin has 2 spines and 23 to 26 rays; their dorsal fin has 13 to 15 dorsal spines and 12 to 14 rays; and, their pectoral fins have 12 or 13 rays.
The Mexican Barnacle Blenny is found in abandoned barnacles, mollusks tubes, and worm tubes on rocky reefs in shallow waters at depths up to 15 m (50 feet). They reach a maximum of 6.0 cm (2.4 inches) in length. They enter tail first in the various types of shelter in which they reside and are found with only their head exposed. They are known to have very poor eyesight and to exhibit fearless and extremely aggressive behavior in captivity and will attack anything large or small that approaches their home. They feed primarily on zooplankton. The Mexican Barnacle 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 Mexican Barnacle Blenny is a resident of Mexican waters of the Pacific Ocean but has a limited distribution being found from Mazatlán, Sinaloa to Guatemala along the coast of the mainland.
The Mexican Barnacle Blenny can be confused with the Clubhead Barnacle Blenny, Acanthemblemaria balanorum (tan-colored front portion of dorsal fin) and the Cortez Barnacle Blenny, Acanthemblemaria hastingsi (orange-yellow front portion of dorsal fin).
From a conservation perspective the Mexican Barnacle Blenny is currently considered to be of Least Concern with stable widely distributed populations. They are utilized by the aquarium trade and are highly prized for their entertainment value as they are highly vigilant and make mad dashes out of hiding before retreating to obtain food. They can be found for sale on the internet. They are also valued as photographic subjects with their photographs also being offered on the internet. In general, however, they too small to be of interest to most.