Malacoctenus gilli, the Dusky blenny, is a species of labrisomid blenny native to the Atlantic Ocean including the Gulf of Mexico and the Caribbean Sea from the Bahamas to the north coast of South America. This species inhabits reef patches, areas of sandy substrates with available rocks and beds of seagrass at depths of from 1 to 5 metres (3.3 to 16.4 ft). It can reach a length of 7.6 centimetres (3.0 in) TL.