The obscure snakehead, ''Parachanna obscura'', is a medium-sized

carnivorous fish Predatory fish are hypercarnivorous fish that actively prey upon other fish or aquatic animals, with examples including shark, billfish, barracuda, pike/muskellunge, walleye, perch and salmon. Some omnivorous fish, such as the red-bellied piran ...

that has an elongated shape tapered on both ends and is covered in medium circular scales (

cycloid In geometry, a cycloid is the curve traced by a point on a circle as it rolls along a straight line without slipping. A cycloid is a specific form of trochoid and is an example of a roulette, a curve generated by a curve rolling on another cu ...

). The head, resembling a snake, is long and depressed anteriorly and covered with cycloid scales slightly larger than those scales on the body. This species is found in central Africa along the western coastline from as far north as Senegal to as far south as Zaire and into central Africa into southwest Sudan.

Geographic range

Four identified ''

Parachanna ''Parachanna'' is a genus of snakeheads native to freshwater habitats in tropical Africa. Three recognized extant (living) species are in this genus, but a phylogenetic study from 2017 indicates that a fourth, currently undescribed species also ...

'' species originate within the continent of

Africa Africa is the world's second-largest and second-most populous continent, after Asia in both cases. At about 30.3 million km2 (11.7 million square miles) including adjacent islands, it covers 6% of Earth's total surface area ...

. They include ''P. fayumensis'' (fossil), ''P. africana'', ''P. insignis'', and the most common, ''P. obscura''. ''P. africana'' is restricted to Benin, Nigeria, and into Gabon, ''P. insignis'' is found throughout the

Congo River basin The Congo River ( kg, Nzâdi Kôngo, french: Fleuve Congo, pt, Rio Congo), formerly also known as the Zaire River, is the second longest river in Africa, shorter only than the Nile, as well as the second largest river in the world by discharge ...

in Congo and into

Gabon Gabon (; ; snq, Ngabu), officially the Gabonese Republic (french: République gabonaise), is a country on the west coast of Central Africa. Located on the equator, it is bordered by Equatorial Guinea to the northwest, Cameroon to the nort ...

, and ''P. obscura'' is the most widespread of the African species, being found in the Lake Chad basin, and the

Nile The Nile, , Bohairic , lg, Kiira , Nobiin: Áman Dawū is a major north-flowing river in northeastern Africa. It flows into the Mediterranean Sea. The Nile is the longest river in Africa and has historically been considered the longest ...

Zaire Zaire (, ), officially the Republic of Zaire (french: République du Zaïre, link=no, ), was a Congolese state from 1971 to 1997 in Central Africa that was previously and is now again known as the Democratic Republic of the Congo. Zaire was, ...

Cross A cross is a geometrical figure consisting of two intersecting lines or bars, usually perpendicular to each other. The lines usually run vertically and horizontally. A cross of oblique lines, in the shape of the Latin letter X, is termed a sa ...

Niger ) , official_languages = , languages_type = National languagesSenegal River basins. Parachanna distribution

Morphology

''Parachanna obscura'' is a medium-sized

with an elongated shape tapered on both ends, and is covered in medium circular scales (

). The head, resembling a snake, is long and depressed anteriorly and covered with cycloid scales slightly larger than those scales on the body. The eyes are laterally located, large, and help the fish to locate its prey quickly. Two pairs of nostrils occur on either side of the head. The mouth is large, and because the lower jaw is slightly longer than the upper jaw, the fish is able to thrust out its lower jaw (protract) to catch its prey. The fish has two rows of teeth. The outer row consists of small, sharp, conical teeth, and the inner row consists of four to six large canines. ''P. obscura'' has a single lateral line. The coloration of ''P. obscura'' adults and juveniles consists of dark blackish, rounded spots found along the flanks. The

ventral side Standard anatomical terms of location are used to unambiguously describe the anatomy of animals, including humans. The terms, typically derived from Latin or Greek roots, describe something in its standard anatomical position. This position prov ...

of the fish has a yellowish, reddish, and brownish marbling coloration. Dark spots on the back and lateral dark bands on the head help to define the fish. A baby fish initially has an ochre base coloration with a black stripe down its flank from the snout to the

caudal fin Fins are distinctive anatomical features composed of bony spines or rays protruding from the body of a fish. They are covered with skin and joined together either in a webbed fashion, as seen in most bony fish, or similar to a flipper, as ...

. ''P.obscura'' larvae are yellow in color.

Habitat

The obscure snakehead is both

benthopelagic The demersal zone is the part of the sea or ocean (or deep lake) consisting of the part of the water column near to (and significantly affected by) the seabed and the benthos. The demersal zone is just above the benthic zone and forms a layer of ...

(bottom dweller) and

potamodromous Fish migration is mass relocation by fish from one area or body of water to another. Many types of fish migrate on a regular basis, on time scales ranging from daily to annually or longer, and over distances ranging from a few metres to thousan ...

(freshwater migratory), and thrives in harsh environments, including muddy waters. This fish lives in streams,

pond A pond is an area filled with water, either natural or artificial, that is smaller than a lake. Defining them to be less than in area, less than deep, and with less than 30% emergent vegetation helps in distinguishing their ecology from ...

river A river is a natural flowing watercourse, usually freshwater, flowing towards an ocean, sea, lake or another river. In some cases, a river flows into the ground and becomes dry at the end of its course without reaching another body of w ...

lake A lake is an area filled with water, localized in a basin, surrounded by land, and distinct from any river or other outlet that serves to feed or drain the lake. Lakes lie on land and are not part of the ocean, although, like the much large ...

marshes A marsh is a wetland that is dominated by herbaceous rather than woody plant species.Keddy, P.A. 2010. Wetland Ecology: Principles and Conservation (2nd edition). Cambridge University Press, Cambridge, UK. 497 p Marshes can often be found at ...

lagoon A lagoon is a shallow body of water separated from a larger body of water by a narrow landform, such as reefs, barrier islands, barrier peninsulas, or isthmuses. Lagoons are commonly divided into ''coastal lagoons'' (or ''barrier lagoons'') ...

s, swamps, and

floodplain A floodplain or flood plain or bottomlands is an area of land adjacent to a river which stretches from the banks of its channel to the base of the enclosing valley walls, and which experiences flooding during periods of high discharge.Goudi ...

s. The obscure snakehead is also known as the “sleeping fish”, as it spends much of its time motionless among the

aquatic vegetation Aquatic plants are plants that have adapted to living in aquatic environments (saltwater or freshwater). They are also referred to as hydrophytes or macrophytes to distinguish them from algae and other microphytes. A macrophyte is a plant that g ...

. It lives in waters greater than 20 °C and is found primarily within the intertropical convergent zone.

Diet and growth

Obscure snakeheads are

. Adults feed primarily on other fish up to half their size, while juveniles feed on insect larvae,

insects Insects (from Latin ') are pancrustacean hexapod invertebrates of the class Insecta. They are the largest group within the arthropod phylum. Insects have a chitinous exoskeleton, a three-part body (head, thorax and abdomen), three pairs of j ...

, prawns, and copepods. This fish can gain about 2 g/day and reach a weight of 1 kg within 4–5 months. An adult ''P. obscura'' has been measured at 54 cm.

Reproduction

Determining the sex of the obscure snakehead can only be done through the dissection of the

gonads A gonad, sex gland, or reproductive gland is a mixed gland that produces the gametes and sex hormones of an organism. Female reproductive cells are egg cells, and male reproductive cells are sperm. The male gonad, the testicle, produces sper ...

. Reproduction happens throughout the year, especially during and right after flooding. Males and females during

spawning Spawn is the eggs and sperm released or deposited into water by aquatic animals. As a verb, ''to spawn'' refers to the process of releasing the eggs and sperm, and the act of both sexes is called spawning. Most aquatic animals, except for aquat ...

make a color change. The males change from brown to bright blue and the females' brown spots turn a deeper dark brown and the bright spots on their fins turn blue, and both male and female

pectoral fins Fins are distinctive anatomical features composed of bony spines or rays protruding from the body of a fish. They are covered with skin and joined together either in a webbed fashion, as seen in most bony fish, or similar to a flipper, as see ...

turn white at the tips. The female lays her eggs and the male immediately fertilizes them. Incubation time varies depending on the temperature of the water and amount of light to which the eggs are exposed. The adults both share in the responsibility of protecting the young until they reach a length of about 3 mm.

Commercial importance

The obscure snakehead is being considered as an emerging aquaculture species in

. The fish is very fleshy, has few bones, and is high in

protein Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, res ...

. An issue of concern is the way the fish are harvested. The use of poison, fire, and dynamite as fishing tools, along with the improper netting of fish, are hurting the fish population, as well as those humans consuming the fish.

References

{{Taxonbar, from=Q6408520

Obscure snakehead The obscure snakehead, ''Parachanna obscura'', is a medium-sized carnivorous fish that has an elongated shape tapered on both ends and is covered in medium circular scales (cycloid). The head, resembling a snake, is long and depressed anteriorl ...

Fish described in 1861