Kelp Clingfish, Rimicola muscarum

Kelp Clingfish, Rimicola muscarum. Fish caught from coastal waters off Monterey, California, November 2024. Length: 5.1 cm (2.0 inches). Catch, photograph and Identification courtesy of Vince Golder, Santa Cruz, California.

Kelp Clingfish, Rimicola muscarum. Fish caught from coastal waters off Monterey, California, December 2024. Length: 5.2 cm (2.0 inches). Catch, photograph and Identification courtesy of Vince Golder, Santa Cruz, California.

The Kelp Clingfish, Rimicola muscarum, is a member of the Clingfish or Gobiesocidae Family, that is known in Mexico as chupapiedra sargacera. Globally, there are five species in the genus Rimicola, of which two are found in Mexican waters, both in the Pacific Ocean.

The Kelp Clingfish has an elongated slender body with a flat head with a blunt snout that tapers toward the tail. Their mouth has well-developed incisors at the lower front followed on each side by or two weak canines, then a row of small conical teeth, and a deep patch of small conical teeth behind the first row. The upper teeth are pointed and conical with a deep patch toward the front and recurved canine-likes at the sides.  They are cryptically colored to blend into their background being a light olive green to brown and are sexually dimorphic with the females being sparsely covered with large reddish-brown spots. The juveniles are similar in appearance to the adults. The anal fin has 6 to 8 rays, the caudal fin is narrow and rounded; the dorsal fin has 6 to 8 rays; the pelvic fins are united anteriorly to form a small adhesive disk; and the pectoral fins are short wit h 14 to 19 rays. They have 5 or 6 gill rakers on each arch.

The Kelp Clingfish is a benthic species that is found in the intertidal zone at depths up to 5 m (17 feet).  They reside within kelp beds attaching to the blades with their disks. They spend their entire life. They are most often found in the canopy of the kelp forest but also can be found near the holdfast. They can be found attached to kelp growing from the edges of docks. They reach a maximum of 7.0 cm (2.8 inches) in length. They feed primarily on small crustaceans, isopods, limpets, mollusks and shrimp. In turn they are preyed upon by shorebirds, fish and mammals and rely on hiding and camouflage for survival. The Kelp Clingfish is sexually dimorphic and reproduction is oviparous with the eggs deposited in the kelp frons. The Kelp Clingfish is poorly studied with very limited information available about their lifestyle and behavioral patterns including specific details on age, diet, growth, habitat, longevity, movement patterns, and reproduction.

The Kelp Clingfish has a limited distribution in Mexican waters of the Pacific Ocean being found from Punta Baja (El Rosario) northward along the central and northwest coasts of the Baja Peninsula.

The Kelp Clingfish can be easily confused with the Slender Clingfish, Rimicola eigenmanni  (wider head with a more rounded snout).

From a conservation perspective the Kelp Clingfish is currently considered to be of Least Concern being common with stable, widely distributed populations. Their long-term viability is threatened by the global demise of kelp beds, and their high annual variability caused by pollution and human coastal developments. They are too small to be of interest to most. They are small in stature, seldom seen by humans, and of limited interest to most. They are utilized by thd aquarium trade at a nominal level.