Ichthyococcus Phosichthys Pollichthys Polymetme Vinciguerria Woodsia Yarrella Photichthyidae Lightfishes are small stomiiform fishes in the family Phosichthyidae[1][2] The earliest fossils of lightfishes are from Middle Eocene-aged Tethyan marine strata in Georgia.

[3][4] They are very small fishes found in oceans throughout the world: most species grow no longer than 10 cm, while those in the genus Vinciguerria only reach 4 cm or so.

They make up for their small size with abundant numbers: Vinciguerria is thought — with the possible exception of Cyclothone — to be the most abundant genus of vertebrates.

Deep-sea trawls of the Humboldt Current in the southeast Pacific have found that lightfishes make up 85% by mass of mesopelagic fishes, with Vinciguerria lucetia by far the most numerous species.

[5] They are bioluminescent fishes, possessing rows of photophores along their sides, with which they hunt planktonic invertebrates, especially krill, copepods, and planktonic amphipods.