Zig-zag eel

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Zig-zag eel
Tire Track Eel.jpg
Scientific classification Red Pencil Icon.png
Kingdom: Animalia
Phylum: Chordata
Class: Actinopterygii
Order: Synbranchiformes
Family: Mastacembelidae
Genus: Mastacembelus
M. armatus
Binomial name
Mastacembelus armatus
(Lacepède, 1800)
Synonyms [2]
  • Macrognathus armatusLacepède, 1800
  • Mastacembelus ponticerianus Cuvier, 1832
  • Mastacembelus marmoratusCuvier, 1832
  • Macrognathus caudatus McClelland, 1842
  • Macrognathus hamiltoniiMcClelland, 1844
  • Mastacembelus manipurensis Hora, 1921

The zig-zag eel (Mastacembelus armatus), also known as the tire-track eel, tire-track spiny eel or marbled spiny eel, [2] is a species of ray-finned, spiny eels belonging to the genus Mastacembelus (Scopoli, 1777) [3] of the family Mastacembelidae, and is native to the riverine fauna of India, Bangladesh, Pakistan, Sri Lanka, Thailand, Vietnam, Indonesia and other parts of Southeast Asia. The species was described as Macrognathus armatus by Lacepède in 1800. [4] Other common names for this popular aquarium species are leopard spiny eel [5] and white-spotted spiny eel. This species is not only a popular aquarium fish but also as a food fish in its country of origin. [6] [2]



Mastacembulus armatus Swaine.jpg

Mastacembelus armatus is a large elongated fish that has a snake-like body without pelvic fins. Its anal and dorsal fins are elongated and are connected to the caudal fin. The dorsal fin is preceded by numerous spines. [7] The back is dark beige in color while the head is silver-beige. The body's color is dull brown and the belly is a lighter shade of brown. The body may also be marked with brown circular patterns. The body also have one to three darker longitudinal zigzag lines that connect to form a distinct reticulated pattern that is restricted to the dorsal two-thirds of the body. The eyes have brown stripes running laterally through them. [6] [2]

Mastacembelus armatus can reach up to 36" (91 cm) in its natural habitat but does not usually exceed 20" (51 cm) in captivity. [6] [2]

Despite its eel-like appearance, Mastacembelus armatus is not considered a true eel. [7]


Mastacembelus armatus are nocturnal fish that thrive in highland streams, lowland wetlands, still waters, coastal marshes and rivers with sandy or rocky riverbeds and heavy vegetation. They are common during the tropical summer months and will dwell in canals, lakes and other floodplain areas during the flood season. [6] [2]

In the aquarium

Tire track eel hiding in a decorative car TireTrackEels2.jpg
Tire track eel hiding in a decorative car

Aquarium maintenance

Mastacembelus armatus are bottom dwellers and occasional substrate diggers [7] and burrowers. Those that are 6" (15 cm) long do well in tanks measuring 36" (91 cm) with a capacity of 35 gallons (132 liters). However, larger M. armatus necessitate aquariums measuring at least 48" (122 cm) with 55 gallons (209 liters) capacity. Zig-zag eels do well in freshwater or slightly brackish aquatic environments (produced by adding two teaspoons of sea salt (not iodated) per 212 gallons of water) [7] with 6 to 25 dH water hardness, with pH readings ranging from 6 to 8, and temperatures that are maintained between 73 and 81 °F (23 to 27 °C). [6] [2]

M. armatus tend to uproot plants and disturb decorations. [7]


Although zig-zag eels are often combined with medium to large-sized gouramis, knifefish, danios, loaches, Loricariids, eartheaters, acaras, Cichlasomines and Asian catfishes in a community fish aquarium, they are not normally mixed with small-sized fish, because tire track eels are observed to prey upon smaller fish. Mixing them with fish belonging to the same species is also not recommended. [6] [2] This is because they are aggressive to members of the same fish family but peaceful to other fish species with similar care level requirements, size and temperament. [7] [8]


Being nocturnal carnivores, zig-zag eels forage on benthic insect larvae, earthworms, blackworms and some submerged plant material. In an aquarium setting, they require live foods in their diet such as live fish, tubifex worms, brine shrimps, mosquito larvae, frozen bloodworms, cyclops, krill and ocean plankton. [6] [2] [7]


Male and female zig-zag eels are only distinguishable when mature. Females are normally plumper than males. Although their fecundity in the wild is high, there are no known successful breeding programs in captivity. [6] [2]

Related Research Articles

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The name spiny eel is used to describe members of two different families of fish: the freshwater Mastacembelidae of Asia and Africa, and the marine Notacanthidae. Both are so-named because of their eel-like shape and sturdy fin spines. These two families are not related: the Notacanthiformes belong to the Superorder Elopomorpha, whose members are characterized by having leptocephalus larvae. The freshwater Mastacembelids do not share this characteristic and are popular specimens in the aquarium trade.

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Mastacembelus is a genus of many species of spiny eel fish from the family Mastacembelidae. They are native to Africa and Asia. Most are found in rivers and associated systems, but there are also species in other freshwater habitats and a particularly rich radiation is found in the Lake Tanganyika basin with 15 species. A few species can even occur in brackish water.

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<i>Mastacembelus platysoma</i> Species of fish

Mastacembelus platysoma is a species of fish, a spiny eel in the family Mastacembelidae. It is found in Lake Tanganyika which is bordered by Burundi, the Democratic Republic of the Congo, Tanzania and Zambia. The IUCN has listed it as being of "Least Concern".

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Macrognathus fasciatus is a species of spiny eel found in the Manimala River and first described in 2014. Macrognathus fasciatus differs from its relative species by the presence of 28–30 dorsal spines, 26–27 vertical lateral lines on the body, 8–9 whitish yellow round spots present in a row in between every two vertical lines and first dorsal spine originate at the level or a little behind the end of pectoral fin.


  1. Fernado, M.; Kotagama, O.; de Alwis Goonatilake, S. (2019). "Mastacembelus armatus". IUCN Red List of Threatened Species . 2019: e.T166586A60592409. doi: 10.2305/IUCN.UK.2019-3.RLTS.T166586A60592409.en . Retrieved 19 November 2021.
  2. 1 2 3 4 5 6 7 8 9 10 Froese, Rainer; Pauly, Daniel (eds.) (2019). "Mastacembelus armatus" in FishBase . August 2019 version.
  3. Integrated Taxonomic Information System, National Museum of Natural History, Washington, D.C., Mastacembelus armatus (Lacepède, 1800), Taxonomic Serial No.: 172692, 2007, retrieved on:5 June 2007.
  4. Eschmeyer, William N.; Fricke, Ron & van der Laan, Richard (eds.). "'Macrognathus armatus". Catalog of Fishes . California Academy of Sciences . Retrieved 13 November 2019.
  5. Leopard spiny eel (Mastacembelus armatus), BangkokAquarium.com, Bangkok, Thailand, 2006, retrieved on: 5 June 2007.
  6. 1 2 3 4 5 6 7 8 Butler, Rhett Ayers, Tire track Eel, Spiny Eel, White-spotted Spiny Eel (Mastacembelus armatus), Tropical Freshwater Aquarium Fish (TFAF), 1995 and Mongabay.com, 2006, retrieved on: 5 June 2007.
  7. 1 2 3 4 5 6 7 Foster and Smith, Veterinary & Aquatic Services Department, Drs. Foster & Smith, Inc., PetEducation.com, 2007, retrieved on: 5 June 2007.
  8. Tire Track Eel (Mastacembelus armatus), Aqua-Fish.net, 2007, retrieved on: 5 June 2007.