Montagu's blenny is small and has an elongated body which has no scales, its eyes are set on top of the head and its mouth points downwards. It attains a
Total Length of . The background colour is pale brown marked with olive-green vertical stripes and light blue spots. There is a single
dorsal fin that runs along the total length of its body with an obvious notch part of the way along. There is fringed, fleshy crest situated between its eyes and, in at least in Britain and Ireland, this feature distinguishes Montagu's blenny from the other species present. The fleshy crest continues along the dorsal surface of the blenny as a series of short fleshy tentacles. It has large
pectoral fins which are used to grip on to rock surfaces and resemble limbs. The fish in the Atlantic specimens often have dark-spots compared to Mediterranean populations. When
spawning the males become uniformly dark or show a marbled pattern and have a white upper lip. ==Distribution==