Measures at most 12 cm in length. It has a very wide and flattened head. It has two dorsal fins, and very wide pectoral fins. The radii of the fins show several lines of dark spots. Body color is dark brown or blackish, with irregular spots.

It is endemic to the upper Garonne basin, both in the Aran Valley and in French territory.

It lives in the high sections of the rivers, in cold water and strong current, hidden among the stones in the background. It reproduces in spring. Males prepare a nest under a stone where the female lays her eggs. The male takes care of the eggs until the time of hatching. It feeds on invertebrates, but it can also catch fish fry.

Its populations are currently very sparse due to habitat degradation, hydroelectric alterations and channelization.