Butterfly blenny Butterfly blenny The butterfly blenny ("Blennius ocellaris") is a small marine blenniid fish of Northern and Western Europe, as well as the Mediterranean and Black Seas and Morocco. It can grow as large as in length. It is usually found at a depth of down, especially in areas with a rocky floor. The butterfly blenny has 11–12 dorsal spines, 14–16 dorsal soft rays, 2 anal spines and 15–16 anal soft rays. It has tentacles on the nasal opening, above the eye and on the nape near the first dorsal fin ray. The lateral line is discontinuous. The forward part of
Round goby Nord-Ostsee (Kiel) Canal. As of 2010, the westernmost site of round goby occurrence in Europe was the Lower River Scheldt, the tidal zone in the river mouth, and Albert Canal, Belgium. In 2011, the round goby began invading the fresh waters of France: the species appeared in the Rhine River (on the border between France and Germany), and in the French part of the Moselle River. In total, 52 parasite species are registered in the round goby in the native area. Most abundant parasites of the Black-Sea round goby are metacercariae of trematodes of Heterophyidae family, such as "Cryptocotyle concavum",