Threefin blenny to rock crevices at any perceived threat. Threefin blennies are diurnal and territorial; many species exhibit sexual dichromatism, with the females drab compared to the males. The second dorsal fin is also extended in the males of some species. Small invertebrates comprise the bulk of the threefin blenny diet. FishBase lists about 150 species in 30 genera: Threefin blenny Threefin or triplefin blennies are blennioids, small perciform marine fish of the family Tripterygiidae. Found in tropical and temperate waters of the Atlantic, Pacific and Indian Oceans, the family contains about 150 species in 30 genera. The family name derives from
Grass goby Grass goby The grass goby ("Zosterisessor ophiocephalus") is a species of goby native to the Mediterranean Sea, the Sea of Azov and the Black Sea. It is currently the only known member of its genus. Grass gobies can grow up to long. The head crown, nape, throat, belly, and bases of the pectoral fins are covered by cycloid scales and the gill covers are naked. The abdominal sucker has no blades and does not reach the anus. The mandibulae are protrusive, and the skin soft, with mucus. Their coloration is green-brown, patterned with merging brown spots. The cheeks have round