The beardfishes are a small family

Family (biology)

In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...

 (Polymixiidae) of deep-sea marine ray-finned fish named for their pair of long hyoid barbel

Barbel (anatomy)

A barbel on a fish is a slender, whiskerlike tactile organ near the mouth. Fish that have barbels include the catfish, the carp, the goatfish, sturgeon, the zebrafish and some species of shark...

s. They have little economic importance.

They are found in tropical and subtropical waters of the Atlantic, Indian

Indian Ocean

The Indian Ocean is the third largest of the world's oceanic divisions, covering approximately 20% of the water on the Earth's surface. It is bounded on the north by the Indian Subcontinent and Arabian Peninsula ; on the west by eastern Africa; on the east by Indochina, the Sunda Islands, and...

 and western Pacific Ocean

Pacific Ocean

The Pacific Ocean is the largest of the Earth's oceanic divisions. It extends from the Arctic in the north to the Southern Ocean in the south, bounded by Asia and Australia in the west, and the Americas in the east.At 165.2 million square kilometres in area, this largest division of the World...

. They are bottom-dwelling fish, found down to about 800 metres (2,624.7 ft) depth. Most are relatively small fish, although one species is over 40 centimetres (15.7 in) in length.

Classification

Ten species of the single extant genus Polymixia are known, along with several fossil genera.

At present they are classified in their own order Polymixiiformes, but as Nelson says, "few groups have been shifted back and forth as frequently as this one". For instance, they have previously been classified as belonging to the Beryciformes

Beryciformes

Beryciformes is an order of ray-finned fishes. This is a very poorly understood group of 16 families, 57 genera, and about 219 species. Some people believe that it is probably an artificial assemblage of unrelated taxa that are thrown together for convenience only; there are no convincing...

.

Order Polymixiiformes

• Family Polymixiidae
  • Genus Polymixia
    • Beardfish, Polymixia lowei Günther, 1859.
    • Pacific beardfish, Polymixia berndti Gilbert, 1905.
    • Polymixia salagomeziensis Kotlyar, 1991.
    • Polymixia fusca Kotthaus, 1970.
    • Polymixia yuri Kotlyar, 1982.
    • Polymixia longispina Deng, Xiong & Zhan, 1983.
    • Stout beardfish, Polymixia nobilis
      Polymixia nobilis
      Polymixia nobilis is a species of beardfish. The species can grow up to 20 inches. The species live on both sides of the Atlantic Ocean on gravel and sandy bottoms. Scientists do not know how they behave or reproduce. The species's dorsal fin has five spines and 34-27 soft rays. The habitat of...
      
      Lowe, 1838.
    • Polymixia busakhini Kotlyar, 1993.
    • Polymixia sazonovi Kotlyar, 1992.
    • Silver eye, Polymixia japonica Günther, 1877.