''Mastacembelus'' 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 many species of spiny eel fish from the family

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 ...

. They are native to Africa (c. 45 species) and Asia (c. 15 species). Most are found in rivers and associated systems (even in

rapids Rapids are sections of a river where the river bed has a relatively steep stream gradient, gradient, causing an increase in water velocity and turbulence. Flow, gradient, constriction, and obstacles are four factors that are needed for a rapid t ...

), but there are also species in other freshwater habitats and a particularly rich

radiation In physics, radiation is the emission or transmission of energy in the form of waves or particles through space or a material medium. This includes: * ''electromagnetic radiation'' consisting of photons, such as radio waves, microwaves, infr ...

is found in the

Lake Tanganyika Lake Tanganyika ( ; ) is an African Great Lakes, African Great Lake. It is the world's List of lakes by volume, second-largest freshwater lake by volume and the List of lakes by depth, second deepest, in both cases after Lake Baikal in Siberia. ...

basin with 15 species (14

endemic Endemism is the state of a species being found only in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also foun ...

). A few species can even occur in

brackish water Brackish water, sometimes termed brack water, is water occurring in a natural environment that has more salinity than freshwater, but not as much as seawater. It may result from mixing seawater (salt water) and fresh water together, as in estuary ...

Appearance

The size and pattern varies greatly depending on the exact species of ''Mastacembelus''. The smallest are '' M. latens'' and '' M. simba'', which only reach a maximum total length of . At up to , the largest of both the family and this genus is '' M. erythrotaenia''. ''M. erythrotaenia'', often known as the fire eel, is blackish with an orange-red pattern, and it is a 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. Otherwise species in this genus are typically brownish and often have a spotted, speckled or mottled pattern, either in another brown hue, grayish or yellowish. This pattern is reflected in the common name of another species sometimes kept in aquariums, the

zig-zag eel The zig-zag eel (''Mastacembelus armatus'' Scopoli, 1777'), also known as the Baim, tire-track, tire-track spiny-eel, freshwater spiny eel, or marbled spiny eel, is a species of freshwater Actinopterygii, ray-finned fish in the Family (biology), ...

''M. armatus'' (alternatively called the tire track eel, a name otherwise used for '' M. favus''). A few others also occasionally appear in the aquarium trade, and some are considered good food fish and eaten locally. '' M aviceps'', '' M. brichardi'', '' M. crassus'' and '' M. latens'' are found in dark, deep parts of the

Congo River The Congo River, formerly also known as the Zaire River, is the second-longest river in Africa, shorter only than the Nile, as well as the third-largest river in the world list of rivers by discharge, by discharge volume, following the Amazon Ri ...

and sometimes shallower among rocks. These four species have reduced eyes and are all pinkish-white in color (non- pigmented), similar to

cavefish Cavefish or cave fish is a generic term for fresh and brackish water fish adapted to life in caves and other underground habitats. Related terms are subterranean fish, Troglomorphism, troglomorphic fish, troglobitic fish, stygobitic fish, phreat ...

Taxonomy

In an evaluation of the Mastacembelidae in 2005, the genera ''Caecomastacembelus'' and ''Aethiomastacembelus'' (formerly used for the African species) were placed in

synonymy A synonym is a word, morpheme, or phrase that means precisely or nearly the same as another word, morpheme, or phrase in a given language. For example, in the English language, the words ''begin'', ''start'', ''commence'', and ''initiate'' are a ...

with ''Mastacembelus''.

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 63 recognized species in this genus. 5 additional species (marked with a star* in the list) are recognized by

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 ...

. * '' Mastacembelus alboguttatus'' Boulenger, 1893 * '' Mastacembelus albomaculatus''

Poll Poll, polled, or polling may refer to: Forms of voting and counting * Poll, a formal election ** Election verification exit poll, a survey taken to verify election counts ** Polling, voting to make decisions or determine opinions ** Polling pla ...

, 1953 * '' Mastacembelus ansorgii'' Boulenger, 1905 * '' Mastacembelus apectoralis'' K. J. Brown, Britz, I. R. Bills, Rüber & J. J. Day, 2011 * '' Mastacembelus armatus'' ( Lacépède, 1800) (Zig zag eel) * '' Mastacembelus aviceps'' T. R. Roberts & D. J. Stewart, 1976 * '' Mastacembelus batesii''* Boulenger, 1911 * '' Mastacembelus brachyrhinus'' Boulenger, 1899 * '' Mastacembelus brichardi''

, (1958) (Blind spiny eel) * '' Mastacembelus catchpolei'' Fowler, 1936 * '' Mastacembelus congicus'' Boulenger, 1896 * '' Mastacembelus crassus'' T. R. Roberts & D. J. Stewart, 1976 * '' Mastacembelus cryptacanthus'' Günther, 1867 * '' Mastacembelus cunningtoni'' Boulenger, 1906 * '' Mastacembelus dayi'' Boulenger, 1912 –

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. alboguttatus'' according to Catalog of Fishes * '' Mastacembelus decorsei'' Pellegrin, 1919 * '' Mastacembelus dienbienensis'' V. H. Nguyễn & H. D. Nguyễn, 2005 – belongs in genus '' Sinobdella'' according to Catalog of Fishes * '' Mastacembelus ellipsifer'' Boulenger, 1899 * '' Mastacembelus erythrotaenia'' Bleeker, 1850 (Fire eel) * '' Mastacembelus favus'' Hora, 1924 (Tire track eel) * '' Mastacembelus flavidus'' Matthes, 1962 * '' Mastacembelus flavomarginatus''* Boulenger, 1898 * '' Mastacembelus frenatus'' Boulenger, 1901 (Longtail spiny eel) * '' Mastacembelus goro''* Boulenger, 1902 * '' Mastacembelus greshoffi'' Boulenger, 1901 * '' Mastacembelus kadeiensis'' Roberts, 2020 * '' Mastacembelus kakrimensis'' Vreven & Teugels, 2005 * '' Mastacembelus latens'' T. R. Roberts & D. J. Stewart, 1976 * '' Mastacembelus liberiensis'' Boulenger, 1898 * '' Mastacembelus loennbergii'' Boulenger, 1898 * '' Mastacembelus malabaricus''* Jerdon, 1849 * '' Mastacembelus marchei'' Sauvage, 1879 * '' Mastacembelus mastacembelus'' ( J. Banks & Solander, 1794) * '' Mastacembelus micropectus'' Matthes, 1962 * '' Mastacembelus moorii'' Boulenger, 1898 * '' Mastacembelus niger'' Sauvage, 1879 * '' Mastacembelus nigromarginatus'' Boulenger, 1898 * '' Mastacembelus notophthalmus'' T. R. Roberts, 1989 * '' Mastacembelus oatesii'' Boulenger, 1893 * '' Mastacembelus ophidium'' Günther, 1894 * '' Mastacembelus pani''* Endruweit, 2024 * '' Mastacembelus pantherinus'' Britz, 2007 * '' Mastacembelus paucispinis'' Boulenger, 1899 * '' Mastacembelus plagiostomus'' Matthes, 1962 * '' Mastacembelus platysoma''

References

{{Taxonbar, from=Q2233752 Mastacembelidae Taxa named by Giovanni Antonio Scopoli Freshwater fish genera