The Scorpidinae, commonly known as halfmoons, knifefishes and sweeps are a subfamily of the sea chubs, a family of marine

Marine (ocean)

Marine is an umbrella term. As an adjective it is usually applicable to things relating to the sea or ocean, such as marine biology, marine ecology and marine geology...

 fish

Fish

Fish are a paraphyletic group of organisms that consist of all gill-bearing aquatic vertebrate animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish, as well as various extinct related groups...

 in the order Perciformes

Perciformes

The Perciformes, also called the Percomorphi or Acanthopteri, is one of the largest orders of vertebrates, containing about 40% of all bony fish. Perciformes means perch-like. They belong to the class of ray-finned fish and comprise over 7,000 species found in almost all aquatic environments...

. The Scorpidinae are distributed throughout the Pacific and east Indian Ocean

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...

s, with species occurring in the waters of North America

North America

North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...

, South America

South America

South America is a continent situated in the Western Hemisphere, mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere. The continent is also considered a subcontinent of the Americas. It is bordered on the west by the Pacific Ocean and on the north and east...

, Asia

Asia

Asia is the world's largest and most populous continent, located primarily in the eastern and northern hemispheres. It covers 8.7% of the Earth's total surface area and with approximately 3.879 billion people, it hosts 60% of the world's current human population...

, Australia

Australia

Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...

 and numerous islands. Most inhabit the continental shelf

Continental shelf

The continental shelf is the extended perimeter of each continent and associated coastal plain. Much of the shelf was exposed during glacial periods, but is now submerged under relatively shallow seas and gulfs, and was similarly submerged during other interglacial periods. The continental margin,...

 in shallow rock and kelp reef

Reef

In nautical terminology, a reef is a rock, sandbar, or other feature lying beneath the surface of the water ....

s and deeper offshore reefs, whilst others are found well offshore in a pelagic setting. Most of the Scorpidinae are carnivorous, taking a variety of small crustacean

Crustacean

Crustaceans form a very large group of arthropods, usually treated as a subphylum, which includes such familiar animals as crabs, lobsters, crayfish, shrimp, krill and barnacles. The 50,000 described species range in size from Stygotantulus stocki at , to the Japanese spider crab with a leg span...

s, although some are partly herbivorous. A number of the larger species are fished for commercially

Commercial fishing

Commercial fishing is the activity of catching fish and other seafood for commercial profit, mostly from wild fisheries. It provides a large quantity of food to many countries around the world, but those who practice it as an industry must often pursue fish far into the ocean under adverse conditions...

 and recreationally

Angling

Angling is a method of fishing by means of an "angle" . The hook is usually attached to a fishing line and the line is often attached to a fishing rod. Fishing rods are usually fitted with a fishing reel that functions as a mechanism for storing, retrieving and paying out the line. The hook itself...

, and are considered good table fish.

Classification

Fishbase

FishBase

FishBase is a comprehensive database of information about fish species . It is the largest and most extensively accessed online database on adult finfish on the web...

 lists eleven species in four genera under the subfamily Scorpidinae. This is a list of known all extant species.

• Subfamily SCORPIDINAE
  • Genus Bathystethus
    • Grey knifefish
      Grey knifefish
      The grey knifefish, Bathystethus cultratus, is a sea chub of the genus Bathystethus, found in New Zealand.-References:* Tony Ayling & Geoffrey Cox, Collins Guide to the Sea Fishes of New Zealand, ISBN 0-00-216987-8...
      
      , Bathystethus cultratus (Bloch & Schneider, 1801)
    • Bathystethus orientale Regan, 1913
  • Genus Labracoglossa
    • Labracoglossa argenteiventris Peters, 1866
    • Blue knifefish
      Blue knifefish
      The blue knifefish, Labracoglossa nitida, is a sea chub of the genus Labracoglossa, found off eastern Australia, and around offshore islands of the east coast of New Zealand, to depths of 20 m...
      
      , Labracoglossa nitida McCulloch and Waite, 1916
  • Genus Medialuna
    • Medialuna ancietae Chirichigno, 1987
    • Halfmoon
      Halfmoon
      The Halfmoon, or Medialuna californiensis, is a species of edible Pacific fish....
      
      , Medialuna californiensis (Steindachner, 1876)
  • Genus Scorpis
    • Sea sweep, Scorpis aequipinnis Richardson, 1848
    • Scorpis chilensis Guichenot, 1848
    • Banded sweep, Scorpis georgianus Valenciennes, 1832
    • Silver sweep
      Silver sweep
      The silver sweep, Scorpis lineolata, is a sweep of the genus Scorpis, found around eastern Australia and northern New Zealand to depths of about 30 m, over reef areas and off headlands...
      
      , Scorpis lineolata Kner, 1865
    • Blue maomao
      Blue maomao
      The blue maomao, Scorpis violacea, is a sweep of the genus Scorpis, found around eastern Australia and northern New Zealand to depths of a few metres, over reef areas and off headlands...
      
      , Scorpis violacea (Hutton, 1873)