Code Goby, Gobiosoma robustum

Code Goby, Gobiosoma robustrum. Fish caught from within the Indian River Lagoon, Sebastian, Florida, December 2021. Length: 3.8 cm (1.5 inches). Catch, photograph and identification courtesy of Ben Cantrell, Sebastian, Florida.

The Code Goby, Gobiosoma robustrum, is a member of the Goby or Gobiidae Family, and known in Mexico as gobio clave. They are named for its lack of scales. Globally, there are nineteen species in the genus Gobiosoma, of which eleven are found in Mexican waters, six in the Atlantic and five in the Pacific Ocean.

The Code Goby has an elongated short stout body with a rounded head that wider than deep and a minute barbel before the front of the large eyes that are set on top and close together and a terminal mouth that is equipped pointed teeth set in bands on each jaw. They have a series of small dark spots along the mid-flank. Some fish can be very light and other very dark in color with or without bands. Their anal fin has 1 spine and 8 to 10 rays; their caudal fin is rounded; their first dorsal fin has 6 to 8 short spines; their second dorsal fin has 1 spine and 10 to 12 rays; their pectoral fins have 15 to 18 rays; and, their pelvic fins have 1 spine and 5 rays and are fused into a section cup and short not reaching anus. They do not have scales.

The Code Goby is a demersal species that are found in protected highly vegetated areas including seagrass beds in coastal areas including shallow marshes, mud flats, and oyster reefs as solitary and reclusive individuals that take shelter inside empty clam and oyster shells at depths up to 10 m (30 feet). They reach a maximum length of 5.0 cm (2.0 inches). They consume aquatic insects and larvae, amphipods, shrimp and zooplankton. Reproduction is oviparous. They have lifespans of up to four years. They have life spans of up to one year. The Code 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 Code Goby is a resident of Mexican waters of the Atlantic Ocean being found throughout the Gulf of Mexico; they are absent from along the east coast of the Yucatán Peninsula in the Caribbean.

The Code Goby is most likely confused with the Naked Goby, Gobiosoma bosc (9 to 11 body bars, 12 anal rays, 13 dorsal rays), the Rockcut Goby, Gobiosoma grosvenori (9 dorsal rays), the Seaboard Goby, Gobiosoma ginsburgi (6 or 7 white body bars, lateral line with elongated dark spots), the Twoscale Goby, Gobiosoma longipala (long pelvic fins reaching anus) and the Tusked Goby, Risor ruber (brown with dark spots).

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