Redlight Goby, Coryphopterus urospilus

Redlight Goby, Coryphopterus urospilus. Underwater photographs taken in Zihuantanejo Bay, Guerrero, March 2019. Photographs courtesy of Ron Woheau, Zihuantanejo. Identification courtesy of Dr. Phil Hastings, Scripps Institution of Oceanography, La Jolla, California.

Redlight Goby, Coryphopterus urospilus. Underwater photograph taken in Zihuantanejo Bay, Guerrero, December 2019. Photograph and identification courtesy of Maude Jette, Dive Zihuantanejo, www.Divezihuatanejo.com.

The Redlight Goby, Coryphopterus urospilus, is a member of the Goby or Gobiidae Family, and is known in Mexico as gobio semáforo. Globally, there are sixteen species in the genus Coryphopterus of which eight are found in Mexican waters, seven in the Atlantic and this species in the Pacific Ocean.

The Redlight Goby has an elongated body with a rounded to straight head that has a small horizontal mouth. The head and body are semi-transparent, the head has a series of reddish-orange stripes, and, the body and five horizontal rows of reddish-range to brown spots on the sides (that resemble red stoplights). The center of the rear flank has several internal elongated white blotches, the base of the caudal fin has a central dark brown spot with a white spot above and below, and there are a pair of red-orange to brown spots at the base of the pectoral fin. Their anal fin has 1 spine and 8 or 9 rays; their caudal fin is rounded; their first dorsal fin has 6 spines; their second dorsal fin has 1 spine and 8 or 9 rays; their pectoral fins have 19 to 21 rays; and, their pelvic fins are fused into a sucking disc. Their body is covered with large rough scales.

The Redlight Goby is found in coral and rocky reef environments at depths up to 43 m (140 feet). They reach a maximum of 8.0 cm (3.1 inches) in length. They feed primarily on zooplankton and small crustaceans. The Redlight 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 Redlight Goby is a resident of all Mexican waters of the Pacific Ocean with the exception that they are absent north of Guerrero Negro, Baja California, along the central and northwest coasts of Baja.

The Redlight Goby is a straightforward identification with the possible exception being the Spot-back Goby, Tigrigobius janssi (limited to the extreme southern coast of Mexico; head with brown bars and spots; body with 6 dark bars and 3 rows of dark spots).

From a conservation perspective the Redlight Goby is currently considered to be of Least Concern with stable, widely distributed populations. They are small in stature and are of little interest to most. They are utilized by the aquarium trade on a limited basis but require a high level of attention.