| Lightfishes Temporal range: | |
|---|---|
 | |
| Ichthyococcus ovatus | |
Scientific classification  | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Actinopterygii |
| Order: | Stomiiformes |
| Suborder: | Phosichthyoidei |
| Family: | Phosichthyidae Weitzman, 1974 |
| Genera | |
Ichthyococcus | |
| Synonyms | |
Photichthyidae | |
Lightfishes are small stomiiform fishes in the family Phosichthyidae [1] [2]
The earliest fossils of lightfishes are of the genera † Solterichthys Calzoni, Giusberti & Carnevale, 2025 from the Early Eocene of Italy and † Sytchevskia Prokofiev, 2002 from Middle Eocene-aged Tethyan marine strata in Georgia. [3] [4] [5]
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. [6]
They are bioluminescent fishes, possessing rows of photophores along their sides, with which they hunt planktonic invertebrates, especially krill, copepods, and planktonic amphipods. [7]
