''Macrognathus'' is a

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

of eel-like

fish A fish (: fish or fishes) is an aquatic animal, aquatic, Anamniotes, anamniotic, gill-bearing vertebrate animal with swimming fish fin, fins and craniate, a hard skull, but lacking limb (anatomy), limbs with digit (anatomy), digits. Fish can ...

of the

family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...

Mastacembelidae The Mastacembelidae are a family of fishes, known as the spiny eels. The Mastacembelids are part of the Order Synbranchiformes, the swamp eels, which are part of the Actinopterygii (ray-finned fishes). In an evaluation of the family in 2004, the ...

of the

order Order, ORDER or Orders may refer to: * A socio-political or established or existing order, e.g. World order, Ancien Regime, Pax Britannica * Categorization, the process in which ideas and objects are recognized, differentiated, and understood ...

Synbranchiformes Synbranchiformes, often called swamp eels, though that name can also refer specifically to Synbranchidae, is an order of ray-finned fishes that are eel-like but have spiny rays, indicating that they belong to the superorder Acanthopterygii. ...

. These fish are distributed throughout most of

South South is one of the cardinal directions or compass points. The direction is the opposite of north and is perpendicular to both west and east. Etymology The word ''south'' comes from Old English ''sūþ'', from earlier Proto-Germanic ''*sunþa ...

and

Southeast Asia Southeast Asia is the geographical United Nations geoscheme for Asia#South-eastern Asia, southeastern region of Asia, consisting of the regions that are situated south of China, east of the Indian subcontinent, and northwest of the Mainland Au ...

. ''Macrognathus'' species feed on small aquatic

insect Insects (from Latin ') are Hexapoda, hexapod invertebrates of the class (biology), class Insecta. They are the largest group within the arthropod phylum. Insects have a chitinous exoskeleton, a three-part body (Insect morphology#Head, head, ...

larva A larva (; : larvae ) is a distinct juvenile form many animals undergo before metamorphosis into their next life stage. Animals with indirect development such as insects, some arachnids, amphibians, or cnidarians typically have a larval phase ...

e as well as

oligochaete Oligochaeta () is a subclass of soft-bodied animals in the phylum Annelida, which is made up of many types of aquatic and terrestrial worms, including all of the various earthworms. Specifically, oligochaetes comprise the terrestrial megadril ...

Appearance and anatomy

Most ''Macrognathus'' species attain in length, but a few surpass this size, with the largest being ''M. aral'' at up to . ''Macrognathus'' are mostly similar to ''

Mastacembelus ''Mastacembelus'' is a genus of many species of spiny eel fish from the family Mastacembelidae. They are native to Africa (c. 45 species) and Asia (c. 15 species). Most are found in rivers and associated systems (even in rapids), but there are a ...

''. However, they differ in a more modified

rostrum Rostrum may refer to: * Any kind of a platform for a speaker: **dais **pulpit ** podium * Rostrum (anatomy), a beak, or anatomical structure resembling a beak, as in the mouthparts of many sucking insects * Rostrum (ship), a form of bow on naval ...

, which may be slightly to significantly larger and longer than those found in ''Mastacembelus''. This serves not only to find food but also to help gather food.

In the aquarium

A number of species of this genus are popular

aquarium An aquarium (: aquariums or aquaria) is a vivarium of any size having at least one transparent side in which aquatic plants or animals are kept and displayed. fishkeeping, Fishkeepers use aquaria to keep fish, invertebrates, amphibians, aquati ...

fish. These include the lesser spiny eel, ''Macrognathus aculeatus'', the spotfinned spiny eel, ''Macrognathus siamensis'', as well as others.

Species

According to

FishBase FishBase is a global species database of fish species (specifically finfish). It is the largest and most extensively accessed online database on adult finfish on the web.

, there are currently 25 recognized species in this genus. According to

Catalog of Fishes Catalog of Fishes is a comprehensive on-line database and reference work on the scientific names of fish species and genera. It is global in its scope and is hosted by the California Academy of Sciences. It has been compiled and is continuously up ...

, one of these, ''M. malabaricus'', belongs in the genus ''

'' instead of ''Macrognathus'' and another, ''M. taeniagaster'', is considered a

junior synonym In taxonomy, the scientific classification of living organisms, a synonym is an alternative scientific name for the accepted scientific name of a taxon. The botanical and zoological codes of nomenclature treat the concept of synonymy differently. ...

of ''M. circumcinctus''. * ''

Macrognathus aculeatus The lesser spiny eel, ''Macrognathus aculeatus'', is a Southeast Asian tropical freshwater fish belonging to the family (biology), family Mastacembelidae. They are uncommonly found in aquarium, aquaria. Physical characteristics The eel has an u ...

'' (

Bloch Bloch is a surname of German origin. Notable people with this surname include: A *Adele Bloch-Bauer (1881–1925), Austrian entrepreneur *Albert Bloch (1882–1961), American painter *Alexandre Bloch (1857–1919), French painter *Alfred Bloch ( ...

, 1786) (Lesser spiny eel) * ''

Macrognathus albus ''Macrognathus'' is a genus of eel-like fish of the family Mastacembelidae of the order Synbranchiformes. These fish are distributed throughout most of South and Southeast Asia. ''Macrognathus'' species feed on small aquatic insect larvae as wel ...

'' * ''

Macrognathus aral ''Macrognathus aral'', the one-stripe spiny eel, is a small fish from Pakistan, India, Bangladesh, Nepal and Myanmar. It usually is found in running and stagnant waters of freshwater and brackish waters. It is in length. After mating, eggs are ...

'' (

& J. G. Schneider, 1801) (Onestripe spiny eel) * ''

Macrognathus aureus ''Macrognathus'' is a genus of eel-like fish of the family Mastacembelidae of the order Synbranchiformes. These fish are distributed throughout most of South and Southeast Asia. ''Macrognathus'' species feed on small aquatic insect larvae as wel ...

Britz Britz () is a German locality (''Ortsteil'') within the Berlin borough (''Bezirk'') of Neukölln. History The village of ''Britzig'' was first mentioned in 1273. It was incorporated by the 1920 Greater Berlin Act. It is known for being the sit ...

, 2010 * ''

Macrognathus caudiocellatus ''Macrognathus'' is a genus of eel-like fish of the family Mastacembelidae of the order Synbranchiformes. These fish are distributed throughout most of South and Southeast Asia. ''Macrognathus'' species feed on small aquatic insect larvae as wel ...

'' ( Boulenger, 1893) * ''

Macrognathus circumcinctus ''Macrognathus'' is a genus of eel-like fish of the family Mastacembelidae of the order Synbranchiformes. These fish are distributed throughout most of South and Southeast Asia. ''Macrognathus'' species feed on small aquatic insect larvae as wel ...

'' (

Hora Hora may refer to: Companies * Hora (company), a Romanian manufacturer of stringed musical instruments People, real & mythological * Hora (pl. Horae), figure from Greek mythology * Hora (surname) * Hora, a member of the Japanese duo Schwarz St ...

, 1924) * ''

Macrognathus dorsiocellatus ''Macrognathus'' is a genus of eel-like fish of the family Mastacembelidae of the order Synbranchiformes. These fish are distributed throughout most of South and Southeast Asia. ''Macrognathus'' species feed on small aquatic insect larvae as wel ...

, 2010 * ''

Macrognathus fasciatus ''Macrognathus'' is a genus of eel-like fish of the family Mastacembelidae of the order Synbranchiformes. These fish are distributed throughout most of South and Southeast Asia. ''Macrognathus'' species feed on small aquatic insect larvae as wel ...

'' Plamoottil &

Abraham Abraham (originally Abram) is the common Hebrews, Hebrew Patriarchs (Bible), patriarch of the Abrahamic religions, including Judaism, Christianity, and Islam. In Judaism, he is the founding father who began the Covenant (biblical), covenanta ...

, 2014Plamoottil, M. & Abraham, N.P. (2014): ''Macrognathus fasciatus'' (Synbranchiformes; Mastacembelidae) - a new fish species from Kerala, India. ''Journal of Experimental Zoology, India, 17 (1): 49-54.'' * '' Macrognathus guentheri'' ( F. Day, 1865) (Malabar spiny eel) * '' Macrognathus keithi'' ( Herre, 1940) * '' Macrognathus lineatomaculatus''

, 2010 * '' Macrognathus maculatus'' ( G. Cuvier, 1832) (Frecklefin eel) * '' Macrognathus malabaricus'' ( Jerdon, 1849) * '' Macrognathus meklongensis'' T. R. Roberts, 1986 * '' Macrognathus morehensis'' Arunkumar & Tombi Singh, 2000 * '' Macrognathus obscurus''

, 2010 * '' Macrognathus pancalus'' F. Hamilton, 1822 (Barred spiny eel) * '' Macrognathus pavo''

, 2010 * '' Macrognathus pentophthalmos'' ( Gronow, 1854) (

extinct Extinction is the termination of an organism by the death of its Endling, last member. A taxon may become Functional extinction, functionally extinct before the death of its last member if it loses the capacity to Reproduction, reproduce and ...

?) * '' Macrognathus semiocellatus'' T. R. Roberts, 1986 * ''

Macrognathus siamensis ''Macrognathus siamensis'', the peacock eel or spotfin spiny eel, is a spiny eel found in freshwater habitats throughout Southeast Asia. They are commercially important as food and aquarium fish. Distribution The peacock eel is native to the M ...

'' ( Günther, 1861) (Peacock eel) * '' Macrognathus siangensis'' Arunkumar, 2016 * '' Macrognathus taeniagaster'' ( Fowler, 1935) * '' Macrognathus tapirus'' Kottelat & Widjanarti, 2005 * '' Macrognathus zebrinus'' ( Blyth, 1858) (Zebra spiny eel)

References

Mastacembelidae Fish of Southeast Asia {{Synbranchiformes-stub