|Stout Beardfish, (P. nobilis)|
D. E. Rosen & Patterson, 1969
T. N. Gill, 1862
R. T. Lowe, 1838
The beardfishes consist of a single extant genus (Polymixia) in a small family (Polymixiidae) of deep-sea marine ray-finned fish named for their pair of long hyoid barbels. 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. They are of little economic importance.
They are found in tropical and subtropical waters of the Atlantic, Indian and western Pacific Ocean. They are bottom-dwelling fish, found down to about 800 metres (2,600 ft) depth. Most are relatively small fish, although one species is over 40 centimetres (16 in) in length.
There are currently 10 recognized species in this genus: 
- Polymixia berndti C. H. Gilbert, 1905 (Pacific beardfish)
- Polymixia busakhini Kotlyar, 1993 (Busakhin's beardfish)
- Polymixia fusca Kotthaus, 1970
- Polymixia japonica Günther, 1877 (Silver eye)
- Polymixia longispina S. M. Deng, G. Q. Xiong & H. X. Zhan, 1983
- Polymixia lowei Günther, 1859 (Beardfish)
- Polymixia nobilis R. T. Lowe, 1838 (Stout beardfish)
- Polymixia salagomeziensis Kotlyar, 1991
- Polymixia sazonovi Kotlyar, 1992
- Polymixia yuri Kotlyar, 1982
In addition to the extant Polymixia, there are several fossil genera known.
Timeline of genera
- Froese, Rainer, and Daniel Pauly, eds. (2006). "Polymixiiformes" in FishBase. February 2006 version.
- Joseph S. Nelson. Fishes of the World. John Wiley & Sons. ISBN 0-471-54713-1.
- Paxton, John R. (1998). Paxton, J.R. & Eschmeyer, W.N., ed. Encyclopedia of Fishes. San Diego: Academic Press. p. 161. ISBN 0-12-547665-5.
- Froese, Rainer, and Daniel Pauly, eds. (2012). Species of Polymixia in FishBase. April 2012 version.
- Sepkoski, Jack (2002). "A compendium of fossil marine animal genera". Bulletins of American Paleontology 364: p.560. Retrieved 2011-05-17.