Large-scaled Spinycheek Sleeper, Eleotris ambylopsis
Large-scaled Spinycheek Sleeper, Eleotris ambylopsis. Fish caught from the Indian River Lagoon, Sebastian, Florida, November 2023. Length: 10.0 cm (3.9 inches). Catch, photograph and identification courtesy of Chris Moore, Peoria, Arizona.
Large-scaled Spinycheek Sleeper, Eleotris ambylopsis. Fish caught from a coastal steam in Sebastian, Florida, June 2022. Length: 12.4 cm (4.9 inches). Catch, photograph and identification courtesy of Ben Cantrell, Sebastian, Florida. Note: the length of this fish exceeding the maximum known length for the species by 4.1 cm (1.6 inches).
The Large-scaled Spinycheek Sleeper, Eleotris ambylopsis, is a member of the Sleeper or Eleotridae Family, and is known in Mexico as dormilón oscuro. Globally, there are thirty-three species in the genus Eleotris, of which three are found in Mexican waters, two in the Atlantic and one in the Pacific Ocean.
The Large-scaled Spinycreek Sleeper has an elongated body. They have a dark brown body with a slightly arched dorsal profile that has scattered spots on the upper back that transitions to lighter dorsally from the tip of the snout to the caudal fin base. There are two dark stripes radiating posteriorly from the eyes and a large spot at the base of the pectoral fin. Their anal fin is dusky and may have 7 rows of wavy spots, their caudal fin is rounded and has 10 to 14 bars formed by small spots on the rays, their first dorsal fin has a dark stripe along its base and another broken stripe through the middle, their second dorsal fin has 5 to 8 wavy diagonal stripes; their pectoral fins have small spots on their rays; and, the pelvic fins have a limited number of spots. They have a broad depressed head that has a short blunt snout and a large oblique mouth that extends to the middle of the eyes, a projecting lower jaw that is equipped with several rows of fine teeth on the jaws with a row of large canines on the outer rear. They have a strong, forward-pointing embedded spine at the lower rear corner of the gill cover. Their anal fin has 1 spine and 7 or 8 rays, their first dorsal fin has 6 spines, their second dorsal fin has 1 spine and 7 to 9 rays; their pectoral fins have 15 to 18 rays, and their pelvic fins have 1 spine and 5 rays. They have large ctenoid scales that are smooth at the front of the body and rough at the back. They do not have a lateral line.
The adult Large-scaled Spinycheek Sleeper are found predominately in freshwater in floating mats of vegetation or near vegetation, and the juveniles in brackish water environments with water temperatures between 24o and 28oC at depths up to 5 m (16 feet). They can tolerate low quality environments. They reach a maximum of 8.3 cm (3.3 inches) in length. They are a benthic species that take shelter between rocks and undergrowth during the day and emerge at night for feeding. The juveniles are omnivores and the adults are carnivorous and feed on arthropods, crustaceans and small fish. Reproduction is a year round event. The Large-scaled Spiny-cheek Sleeper 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 Large-scaled Spiny-cheek Sleeper can be confused with the the Fat Sleeper, Dormitator maculatus (large bluish blotch above the base of the dorsal fin, dark lines radiating from the eyes, stout body), the Small-scaled Spinycheek Sleeper, Eleotris perniger (bars and lines on the sides), and the Spotted Sleeper, Eleotris picta (uniform body coloration).
The Large-scaled Spinycheek Sleeper is a resident of Mexico’s freshwater systems that drain into the Atlantic Ocean including those of the Gulf of Mexico and along the east coast of the Yucatán Peninsula in the Caribbean.
From a conservation perspective the Large-scaled Spinycheek Sleeper is currently considered to be of Least Concern with stable, widely distributed populations. They are small in stature and of limited interest to most.