Threefin blenny


Threefin or triplefin blennies are blenniiforms, small percomorph 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 the Greek tripteros meaning "with three wings".
With an elongated, typical blenny form, threefin blennies differ from their relatives by having a dorsal fin separated into three parts ; the first two are spinous. The small, slender pelvic fins are located underneath the throat and possess a single spine; the large anal fin may have one or two spines. The pectoral fins are greatly enlarged, and the tail fin is rounded. The New Zealand topknot, Notoclinus fenestratus, is the largest species at 20 cm in total length; most other species do not exceed 6 cm.
Many threefin blennies are brightly coloured, often for reasons of camouflage; these species are popular in the aquarium hobby. As demersal fish, threefin blennies spend most of their time on or near the bottom on coral and rocks. The fish are typically found in shallow, clear waters with sun exposure, such as lagoons and seaward reefs; nervous fish, they retreat 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.

Genera

FishBase lists about 150 species in 30 genera:
image:Fosterygion flavonigrum.jpg|thumb|Yellow-and-black triplefin
Forsterygion flavonigrumCremnochorites Holleman, 1982Crocodilichthys Allen (ichthyologist)|Allen] & Robertson, 1991Cryptichthys Hardy, 1987Enneanectes D.S. Jordan & Evermann, 1895Enneapterygius Rüppell, 1835Forsterygion Whitley & Phillipps, 1939Gilloblennius Whitley & Phillipps, 1939Helcogramma McCulloch & Waite, 1918Helcogrammoides Rosenblatt, 1990Karalepis Hardy, 1984Lepidoblennius Steindachner, 1867Lepidonectes Bussing, 1991Matanui Jawad & Clements, 2004Norfolkia Fowler, 1953Notoclinops Whitley, 1930
image:Notoclinops segmentatus.jpg|thumb|Blue-eyed triplefin
Notoclinops segmentatus Ruanoho Hardy, 1986Springerichthys Shen, 1994Trianectes McCulloch & Waite, 1918Trinorfolkia Fricke, 1994Tripterygion Risso, 1827Ucla Holleman, 1993