Onespot Fringehead, Neoclinus uninotatus

Onespot Fringehead, Neoclinus uninotatus. Fish caught from coastal waters off Tiburon, California, May 2018. Length: 13 cm (5.1 inches). Catch, photograph and identification courtesy of Ben Cantrell, San Diego, California.

Onespot Fringehead, Neoclinus uninotatus. Fish caught from coastal waters off Santa Cruz, California, March 2021. Length: 13 cm (5.1 inches). Catch, photograph and identification courtesy of Chris Moore, Peoria, Arizona.

Onespot Fringehead, Neoclinus uninotatus. Fish caught from coastal waters off Santa Cruz, California, September 2023. Length: 19 cm (7.5 inches). Catch, photograph and identification courtesy of Ben Cantrell, Peoria, Illinois.

Onespot Fringehead, Neoclinus uninotatus. Fish caught from coastal waters off Santa Cruz, California, August 2021. Length: 23 cm (9.1 inches). Catch, photograph and identification courtesy of Luke Ovgard, Klamath Falls, Oregon.

Onespot Fringehead, Neoclinus uninotatus. Fish caught from the coastal waters off San Francisco, California, December 2012. Length: 20 cm (7.9 inches). Catch, photograph and identification courtesy of Eli (obsessiveangling.wordpress.com).

The Onespot Fringehead, Neoclinus uninotatus, is a member of the Tube Blenny or Chaenopsidae Family, and is known in Mexico as tubícola mancha singular. Globally, there are eleven species in the genus Neoclinus, of which three are found in Mexican waters of the Pacific Ocean.

The Onespot Fringehead has an elongated, slender, and moderately compressed body. They are brown overall with 7 relatively broad dark brown bars on their sides. They have one large ocelli between the first and second dorsal spines that is blue-black and bordered by yellow. Their anal fin is elongated with the posterior third being deeper with a row of dark spots at the margin; the caudal fin has 5 rows of spots, their dorsal fin has a very long base with anterior portion twice as long as the posterior portion with one row of spots mid-fin and the pectoral fins are transparent. They have a very large head with cirri over their eyes, a bluntly rounded snout, and a very large mouth that extends well past their eyes. They have prominent lips and numerous conical teeth. They are sexually dimorphic with males having larger ocular cirrus than females. Their anal fin has 2 spines and 26 to 31 rays; their caudal fin is rounded; their dorsal fin has 23 to 27 spines and 14 to 17 rays and extends from the rear of the head to the base of the tail; their pectoral fins have 14 to 16 rays and are large and fan-like; and their pelvic fins are small. They have 14 to 16 gill rakers. They are covered with minute scales.

The Onespot Fringehead is a demersal species that is found along open coastlines over sandy or hard muddy substrate along rocky coastlines and bays at depths up to 55 m (180 feet). They reach a maximum of 25 cm (9.8 inches) in length. They live in various types of shelter, which they enter tail first with only their head exposed, that include rocky crevices and made-made habitat such as tires, bottles and coastal structures such as piers. They are known to have very poor eyesight and to exhibit fearless and extremely aggressive behavior, thus will attack anything large or small that approaches their burrows. They are ambush predators that feed primarily on crustaceans. In turn they are preyed upon by numerous Rockfishes and Sea Basses. Reproduction is oviparous with each female depositing 1,000 to 10,000 eggs in clam burrows, under rocks, in beer bottles that contain sticky material to allow the eggs to attach themselves to the substrate before being fertilized by the males. Both the females and the males guard the eggs until they hatch. They have a lifespan of up to 7 years. The Onespot Fringehead 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 Onespot Fringehead is a resident of Mexican waters of the Pacific Ocean but has a limited distribution being from San Martin Island, Baja California northward along the central and northwest coasts of Baja.

The Onespot Fringehead cannot be confused with the Sarcastic Fringehead, Neoclinus blanchardi (two ocelli spots on the dorsal fin) and the Yellowfin Fringehead, Neoclinus stephensae (no ocelli spots on the dorsal fin).

From a conservation perspective the Onespot Fringehead is currently considered to be of Least Concern with stable, widely distributed samples. They are occasionally and accidentally caught by commercial fishermen and recreational anglers but are difficult to handle due to their teeth. Due to their small stature they are of limited interest to most. However, they are utilized by the aquarium trade at a small level.