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
Monkey goby as amphipods and shrimp. In the Danube lakes Yalpug and Kugurluy, the diet of the monkey goby consists of amphipods, molluscs, and Oligochaeta. In the Khadzhibey Estuary a dozen species of prey make up the diet of monkey goby. Polychaetes, larvae of insects, and shrimp are present in the diet year round. Seasonal dietary additions include crabs such as "Rhithropanopeus harrisii", sea weed such as "Zostera marina", and amphipods such as "Marinogammarus olivii". Certain planktonic crustaceans are also present in the diet of adult gobies. In the northwestern Black Sea, twelve parasite species are known to infect the monkey goby.