Butterfly blenny the dorsal fin is much higher than the remainder of it. It spawns in late spring (as late as June in the English Channel) and hides the eggs under an abandoned shell; the male guards the eggs. 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,
Sand goby rounded. In males, there is a conspicuous dark spot on the anterior dorsal fin and in both sexes there is a black patch on the caudal peduncle. The general colour is sandy brown with indistinct dark blotches and reticulations on the dorsal surface and dark striations on the pale fins. The colour of the male darkens during the breeding season and his fins become more coloured. The average size is about . The sand goby normally lives at greater depths than the common goby. It feeds on small invertebrates living on the seabed especially amphipods. It is well camouflaged and