Threefin blenny

Threefin blennies
Common Triplefin, Forsterygion lapillum
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Actinopterygii
Order:	Perciformes
Family:	Tripterygiidae
Genera
Many; see text

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 approximately 144 species in 20 genera. The family name derives from the Greek tripteros meaning "with three wings".

With an elongate, typical blenny form, threefin blennies differ from their relatives by having a dorsal fin separated into three parts (hence the name); 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 centimetres in total length; most other species do not exceed 6 centimetres.

Many threefin blennies are brightly coloured, often for reasons of camouflage; these species are popular in the aquarium hobby. As benthic 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.

Family Tripterygiidae

• Genus Acanthanectes
• Genus Apopterygion
• Genus Axoclinus
• Genus Bellapiscis
  • Twister, Bellapiscis medius
• Genus Blennodon
• Genus Brachynectes
• Genus Ceratobregma
• Genus Cremnochorites
• Genus Crocodilichthys
• Genus Cryptichthys
• Genus Enneanectes
• Genus Enneapterygius
• Genus Forsterygion
  • Yellow and Black Triplefin, Forsterygion flavonigrum
  • Common Triplefin, Forsterygion lapillum
  • Mottled Triplefin, Forsterygion malcolmi
  • Variable Triplefin, Forsterygion varium
• Genus Gilloblennius
• Genus Grahamina
• Genus Helcogramma
• Genus Helcogrammoides
• Genus Karalepis
  • Scaly-headed Triplefin, Karalepis stewarti
• Genus Lepidoblennius
• Genus Lepidonectes
• Genus Norfolkia
• Genus Notoclinops
  • Blue Dot Triplefin, Notoclinops caerulepunctus
  • Blue-eyed Triplefin, Notoclinops segmentatus
  • Yaldwyn's Triplefin, Notoclinops yaldwyni
• Genus Notoclinus
  • New Zealand Topknot, Notoclinus fenestratus
• Genus Obliquichthys
  • Oblique-swimming Triplefin, Obliquichthys maryannae
• Genus Notoclinus
• Genus Ruanoho
  • Spectacled Triplefin, Ruanoho decemdigitatus
• Genus Springerichthys
• Genus Trianectes
• Genus Trinorfolkia
• Genus Tripterygion
• Genus Ucla

References

• Froese, Rainer, and Daniel Pauly, eds. (2005). "Tripterygiidae" in FishBase. March 2005 version.