Freshwater Goby, Ctenogobius schufeldti

Freshwater Goby, Ctenogobius schufeldti. Fish caught from a freshwater drainage system in Sebastian, Florida, April 2021. Length: 6.6 cm (2.6 inches). Catch, photograph and identification courtesy of Ben Cantrell, Sebastian, Florida.

The Freshwater Goby, Ctenogobius schufeldti, is a member of the Goby or Gobiidae Family, that is also known at the American Freshwater Goby and in Mexico as gobio de agua dulce. Globally, there are twenty-eight species in the genus Ctenogobius, seven of which are found in Mexican waters, five in the Atlantic and two in the Pacific Ocean.

The Freshwater Goby has an elongated robust body. They are tan to translucent in color with a dark stripe that runs from the corner of the mouth to the center of the gill cover. The lower corner of the gill cover has a dark blotch, there are five rectangular dark blotches along the mid-flank. Their caudal fin has six indistinct bars and their dorsal fin is covered with oblique dotted bars. They are sexual dimorphic with the males having a dark streak along the inner most ray of the pelvic fins; the fins are plain in females. Their head has round snout with a slightly oblique mouth that opens in the front that is equipped with larger teeth in the inner row on the top jaw, large recurved canines in the outer mid-lateral row and large eyes that are set toward the front. They have a broad low keel on the nape in front of the dorsal fin. Their anal fin has 1 spine and 9 to 11 rays and their first dorsal fin has seven spines, the first two are elongated in males; their second dorsal fin has 1 spine and 9 to 11 rays; and, their pelvic fins are fused to the disc. The body is covered with large rough scales with the exception of the head which is scaleless.

The Freshwater Goby is found in freshwater bodies and in low salinity upper estuarine marshes and occasionally in open bays and sounds at depths up to 5 m (16 feet). They are able to tolerate salinities up to 21.3 ppt. They reach a maximum of 10.7 cm (4.2 inches). They are an omnivore that consume algae, diatoms, gastropods, ostracods and detritus with amounts varying by season. Reproduction is oviparous. The Freshwater Goby 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 Freshwater Goby is a resident of Mexican waters of the Atlantic Ocean drainage is found along the coast from the Texas border south to Veracruz.

The Freshwater Goby is similar in stature with the Darter Goby, Ctenogobius boleosoma, the Dash Goby, Ctenogobius saepepallens, the Mexican Goby, Ctenogobius claytonii, and the Spottail Goby, Ctenogobius stigmaturus, however, each of these lack the five square spots on the mid-flank.

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