Herwigia is a monospecific genus of deepwater maine ray-finned fish belonging to the family Alepocephalidae, the slickheads. The only species in the genus is Herwigia kreffti, or Krefft's smooth-head, a species found at depths of 1000mto3200mm (3,000feetto10,500feetm) in the oceans. This species grows to a length of 40cm (20inches) SL.