The black-striped pipefish has an extraordinarily elongated, slender body, from to 15 total length cm. The head ends in a tube-shaped snout. The fins are very small.

It is distributed in the coastal areas of the Mediterranean and the Atlantic, where it enters the mouths of rivers and coastal wetlands. In Catalonia it is found mainly in the Ebro delta, and is much scarcer in other wetlands.

It has a preference for sand or silt substrates and abundant submerged vegetation. Reproduction is viviparous. The female lays her eggs in skin folds under the male's tail, where they are incubated until the fry come out. They feed on invertebrates.

Their populations are in decline, mainly by the degradation of the wetlands where they live.