Armless Deepsea Flounder, Neoachiropsetta milfordi (Penrith 1965)

Other Names: Armless Flounder, Finless Flounder, Largemouth Flounder

Armless Deepsea Flounder, Neoachiropsetta milfordi. Source: Australian National Fish Collection, CSIRO. License: CC BY Attribution-Noncommercial

A large brownish-grey 'armless' flounder with darker dorsal and anal fins, sometimes pale spots on the body, and a dark lateral line. The species lacks pectoral fins, and has both eyes on the left side of the head.

Cite this page as:
Bray, D.J. 2023, Neoachiropsetta milfordi in Fishes of Australia, accessed 27 May 2024,

Armless Deepsea Flounder, Neoachiropsetta milfordi (Penrith 1965)

More Info


Off southern and western Tasmania; also off Macquarie Island in the Southern Ocean. Elsewhere the species is circumglobal in the southern temperate and sub-Antarctic waters. Inhabits the outer continental shelf and continental slope, including seamounts, ridges and rises, mostly in deeper waters.


Dorsal fin 117-145; Anal fin 104-124; Pelvic fin 4-7 (both sides);  Gill rakers 0-6+1 + 6-11; Lateral-line scales 142-212;  vertebrae 16-17 + 47-49 = 63-67.
Body depth 2.5-3.3 in SL, head length 3.2-4.3 in SL; eye diameter longer than snout but much shorter than upper jaw, 23-30% HL; mouth large, upper jaw length of eyed side 40-50% HL; interorbital width 6-10% HL. 
Midbody region thick and muscular, the dorsal and ventral margins of body thin and semitransparent (except in large adults). Dorsal head profile distinctly concave. Gill rakers small and pointed. Minute teeth on both sides of jaws. 
Scales on the main part of body with 8-12 recumbent ctenii; the scales near and on the fins have ctenii projecting at an angle away from the plane of the scale.


Feeds on diet consists of shrimps, other crustaceans and fishes.


Taken as incidental bycatch in demersal trawl fisheries.


The species is named for "Mr. C.S. Milford, managing director of the trawling firm, Messrs. Irvin and Johnson (Pty) Ltd, in recognition of generous support for marine biological research."

Species Citation

Mancopsetta milfordi Penrith 1965, Annals of the South African Museum 48(7): 181, figs. 1-2, pl. 3. Type locality: west of Cape Town, South Africa.


Bray, D.J. 2023


Atlas of Living Australia

Armless Deepsea Flounder, Neoachiropsetta milfordi (Penrith 1965)


Evseenko, S.A. 1996. Early development stages of the Southern Ocean flounders (family Achiropsettidae). Voprosy Ikhtiologii 36(3): 411-415 [In Russian. English translation in Journal of Ichthyology 36 (4): 345-349] 

Evseenko, S.A. 1996. Ontogeny and relationships of the flatfishes of the Southern Ocean (Achiropsettidae, Pleuronectoidei). Voprosy Ikhtiologii 36(6): 725-752 [in Russian, English translation in Journal of Ichthyology 36(9): 687-712] 

Evseenko, S.A. 2000. Family Achiropsettidae and its position in the taxonomic and ecological classifications of Pleuronectiformes. Journal of Ichthyology 40(Suppl. 1): 110-138 

Heemstra, P.C. 1990. Achiropsettidae, southern flounders. pp. 408-413, figs 1-5 in Gon, O. & Heemstra, P.C. (eds). Fishes of the Southern Ocean. Grahamstown : J.L.B. Smith Institute of Ichthyology 462 pp.

Hensley, D.A. 1986. Family No. 269: Bothidae. pp. 854-863 in Smith, M.M. & Heemstra, P.C. (eds). Smith's Sea Fishes. Johannesburg : Macmillan South Africa xx + 1047 pp. 144 pls. See ref at BHL

Kotlyar, A.N. 1978. A contribution to the systematics of the "armless" flounders (Pisces, Bothidae) from southwestern Atlantic. Journal of Ichthyology 18(5): 708-721.

Kotlyar, A.N. 1980. The biology of "armless" flounders (Bothidae) from the southwestern Atlantic ocean. Journal of Ichthyology 20(4): 143-147.

McMillan, P.J., Francis, M.P., James, G.D., Paul, L.J., et al. 2019. New Zealand fishes. A field guide to common species caught by bottom, midwater, and surface fishing. New Zealand Aquatic Environment and Biodiversity Report No. 208, 295 pp.

Munroe, T.A. 2015. 240 Family Achiropsettidae. pp. 1682-1686 in Roberts, C.D., Stewart, A.L. & Struthers, C.D. (eds). The Fishes of New Zealand. Wellington : Te Papa Press Vol. 4 pp. 1153-1748.

Munroe, T.A. 2021. Neoachiropsetta milfordi. The IUCN Red List of Threatened Species 2021: e.T143621599A143621639. Accessed on 06 January 2023.

Penrith, M.J. 1965. A new species of flat fish, Mancopsetta milfordi, from South Africa, with notes on the genus Mancopsetta. Annals of the South African Museum 48(7): 181-188 figs 1-2 1 pl See ref at BHL

Yau, C., George, M.J.A., Coggan, R.A. & Criado‐Delgado, J.A. 1996. A preliminary study of two species of flatfish (family: Bothidae) from the south‐west Atlantic. Journal of Fish Biology 49: 330-336.

Yearsley, G.K., Last, P.R. & Ward, R.D. (eds) 1999. Australian Seafood Handbook. Hobart : CSIRO Marine Research 460 pp.

Quick Facts

CAAB Code:37460052

Conservation:IUCN Least Concern

Depth:165-1440 m

Habitat:Seamounts, ridges and rises

Max Size:57 cm SL

Species Image Gallery

Species Maps

CAAB distribution map