Lightfishes are small stomiiform fishes in the family Phosichthyidae 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 are bioluminescent fishes, possessing rows of photophores along their sides, with which they hunt planktonic invertebrates, especially krill.