It is a species of small size that does not exceed 10 cm in length. They have no scales and the body is covered with abundant mucous secretion. The mouth has well-developed lips, with relatively large, sharp teeth. The dorsal fin is very long. Body color is very variable, but usually presents brown or yellowish hues, with some dark, irregular bands. The male has a crest on his head.

It is a species native to the entire Mediterranean. In Catalonia it is present in the main rivers (Ebro and tributaries, Ter basin, Fluvià and Llobregat.

It lives in the lower and middle reaches of rivers, but it also adapts to living in lakes and reservoirs. It is located mainly in areas of current, where he lives hidden among the stones. Requires clean or only lightly polluted water. They make nests under the stones, where the male protects the eggs from predators. It feeds on invertebrates and can occasionally prey on fry from other fish.

Feshwater blenny populations are threatened by pollution, water extractions, the introduction of exotic species and habitat alterations.