''Idiacanthus atlanticus'', the black dragonfish, is a
barbeled dragonfish of the
family Stomiidae, found circumglobally in southern subtropical and temperate oceans between latitudes 25°S and 60°S, at depths down to . The species is
sexually dimorphic: females are black with six stripes; males are brown, and lack the females' canine teeth, pelvic fins and barbel. Females are believed to make a
diel vertical migration
Diel vertical migration (DVM), also known as diurnal vertical migration, is a pattern of movement used by some organisms, such as copepods, living in the ocean and in lakes. The word ''diel'' comes from the Latin ''dies'' day, and means a 24-h ...
from deeper than by day to surface waters at night, whereas males do not migrate, remaining below at all times.
Length is up to for the female, but only for the male. Black dragonfish are
bioluminescent
Bioluminescence is the production and emission of light by living organisms. It is a form of chemiluminescence. Bioluminescence occurs widely in marine vertebrates and invertebrates, as well as in some Fungus, fungi, microorganisms including ...
, but unlike most such predators, which use their light primarily to attract prey, they can see their own light. As a result, the fish can use their light to hunt. The light is nearly in the
infrared and barely visible to the human eye.
In the larval stage, the eyes of the larvae appear as long stalks that dangle out of the body. Eventually, they retreat as the fish ages and reaches maturity.
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References
{{Taxonbar, from=Q518838
Stomiidae
Taxa named by August Brauer
Fish described in 1906