Clingfishes and Singleslits: Gobiesocoidei

Physical characteristics: Sonora clingfish have a long thin body with a broad head and a large sucking disk. There are light diagonal stripes along the entire body and a pair of spots just behind the head. Sonora clingfish grow to a length of about 3 inches (8 centimeters).

Geographic range: Sonora clingfish live in the Gulf of California, off Mexico.

Habitat: Sonora clingfish live under rocks, to which they cling, and in little or no water. If kept moist, these fish can withstand extreme temperatures when exposed to air.

Sonora clingfish live under rocks, to which they cling, and in little or no water. (Illustration by Bruce Worden. Reproduced by permission.)

Diet: Sonora clingfish hunt during the day for small crustaceans and mollusks, such as barnacles and limpets. Crustaceans (krus-TAY-shuns) are water-dwelling animals that have jointed legs and a hard shell but no backbone. Mollusks (MAH-lusks) are animals with a soft, unsegmented body that may or may not have a shell.

Behavior and reproduction: Sonora clingfish are secretive, clinging to the undersides of rocks and moving over rocky surfaces to feed. Their movements are related to tidal movements. Activity is greater at high tide, and there is little or no activity at low tide. Males are territorial. Both males and females produce large amounts of mucus, which coats their bodies and protects the fish from drying out.

Sonora clingfish form pairs to mate at the bottom of their habitat. A single male may mate with more than one female. Eggs are sticky and are laid on the underside of rocks, where they are guarded by the male, sometimes with the aid of one or more females. During low tide, the parents secrete mucus that protects the eggs from exposure. The larvae drift in the water.

Sonora clingfish and people: Sonora clingfish sometimes are collected for aquariums.

Conservation status: Sonora clingfish are not threatened or endangered. ∎