The weatherfish (''Misgurnus fossilis'') is a species of

true loach Cobitidae, also known as the true loaches, is a family of Old World freshwater fish. They occur throughout Eurasia and in Morocco, and inhabit riverine ecosystems. Today, most "loaches" are placed in other families (see below). The family includes ...

that has a wide range in

Europe Europe is a continent located entirely in the Northern Hemisphere and mostly in the Eastern Hemisphere. It is bordered by the Arctic Ocean to the north, the Atlantic Ocean to the west, the Mediterranean Sea to the south, and Asia to the east ...

and some parts of

Asia Asia ( , ) is the largest continent in the world by both land area and population. It covers an area of more than 44 million square kilometres, about 30% of Earth's total land area and 8% of Earth's total surface area. The continent, which ...

. It is an omnivorous scavenger bottom feeder, using its sensitive

barbels In fish anatomy and turtle anatomy, a barbel is a slender, whisker like sensory organ near the mouth (sometimes called whiskers or tendrils). Fish that have barbels include the catfish, the carp, the goatfish, the hagfish, the sturgeon, the z ...

to find edible items. The diet mostly consists of small aquatic invertebrates along with some

detritus In biology, detritus ( or ) is organic matter made up of the decomposition, decomposing remains of organisms and plants, and also of feces. Detritus usually hosts communities of microorganisms that colonize and decomposition, decompose (Reminera ...

. The weatherfish is long and thin which allows it to burrow through the substrate and navigate through places that deeper bodied fish would have trouble with. It grows up to in

total length Fish measurement is the measuring of individual fish and various parts of their anatomies, for data used in many areas of ichthyology, including taxonomy and fishery biology. Overall length Standard length (SL) is the length of a fish measured f ...

, though there are fishermen who say they have caught longer, up to . If true, this would make ''Misgurnus fossilis'' the largest species of

This loach has a very wide range, especially in Europe. It occurs north of the

Alps The Alps () are some of the highest and most extensive mountain ranges in Europe, stretching approximately across eight Alpine countries (from west to east): Monaco, France, Switzerland, Italy, Liechtenstein, Germany, Austria and Slovenia. ...

, from the

Meuse River The Meuse or Maas is a major European river, rising in France and flowing through Belgium and the Netherlands before draining into the North Sea from the Rhine–Meuse–Scheldt delta. It has a total length of . History From 1301, the upp ...

in western Europe all the way to the

Neva River The Neva ( , ; , ) is a river in northwestern Russia flowing from Lake Ladoga through the western part of Leningrad Oblast (historical region of Ingria) to the Neva Bay of the Gulf of Finland. Despite its modest length of , it is the fourth-l ...

in northwestern

Russia Russia, or the Russian Federation, is a country spanning Eastern Europe and North Asia. It is the list of countries and dependencies by area, largest country in the world, and extends across Time in Russia, eleven time zones, sharing Borders ...

. It also occurs in the northern part of the

Black Sea The Black Sea is a marginal sea, marginal Mediterranean sea (oceanography), mediterranean sea lying between Europe and Asia, east of the Balkans, south of the East European Plain, west of the Caucasus, and north of Anatolia. It is bound ...

basin from the

Danube River The Danube ( ; see also other names) is the second-longest river in Europe, after the Volga in Russia. It flows through Central and Southeastern Europe, from the Black Forest south into the Black Sea. A large and historically important riv ...

to the

Kuban River The Kuban is a river in Russia that flows through the Western Caucasus and drains into the Sea of Azov. The Kuban runs mostly through Krasnodar Krai for , but also in the Karachay–Cherkess Republic, Stavropol Krai and the Republic of Adygea. ...

, and in the

Caspian Sea The Caspian Sea is the world's largest inland body of water, described as the List of lakes by area, world's largest lake and usually referred to as a full-fledged sea. An endorheic basin, it lies between Europe and Asia: east of the Caucasus, ...

in the River Volga and River Ural drainages. It is also introduced in a few different areas, but not to the extent of the

pond loach The pond loach (''Misgurnus anguillicaudatus''), also known as the Dojo loach, oriental weatherloachGomon, M.F. & Bray, D.J. (2020)Oriental Weatherloach, ''Misgurnus anguillicaudatus'' (Cantor 1842) ''Fishes of Australia'', Museums Victoria. Ret ...

(''Misgurnus anguillicaudatus''). Adult weatherfish live in dense patches of aquatic vegetation while juveniles prefer to live near the shoreline in very shallow water where there is a lot of

; neither adults nor juveniles are found in open areas without vegetation. Because of their habitat preferences,

dredging Dredging is the excavation of material from a water environment. Possible reasons for dredging include improving existing water features; reshaping land and water features to alter drainage, navigability, and commercial use; constructing d ...

and aquatic weed removal poses a danger to weatherfish populations. The weatherfish is listed as

least concern A least-concern species is a species that has been evaluated and categorized by the International Union for Conservation of Nature (IUCN) as not being a focus of wildlife conservation because the specific species is still plentiful in the wil ...

but is protected in most of its range. They are able to survive in habitats that many other fish would be unable to because of their ability to breathe atmospheric oxygen. In low oxygen conditions, the weatherfish will swim to the surface and gulp air. The air then goes through the intestines where a complex system of blood vessels extracts the oxygen, before expelling the air from the anus.

References

Misgurnus Freshwater fish of Europe Fish described in 1758 Taxa named by Carl Linnaeus Taxonomy articles created by Polbot Habitats Directive species {{Cobitidae-stub