Cobitidae, also known as the True loaches, is a

family Family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its members and of society. Idea ...

Old World The "Old World" is a term for Afro-Eurasia that originated in Europe , after Europeans became aware of the existence of the Americas. It is used to contrast the continents of Africa, Europe, and Asia, which were previously thought of by th ...

freshwater Fresh water or freshwater is any naturally occurring liquid or frozen water containing low concentrations of dissolved salts and other total dissolved solids. Although the term specifically excludes seawater and brackish water, it does in ...

fish Fish are aquatic, craniate, gill-bearing animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish as well as various extinct related groups. Approximately 95% ...

. They occur throughout

Eurasia Eurasia (, ) is the largest continental area on Earth, comprising all of Europe and Asia. Primarily in the Northern and Eastern Hemispheres, it spans from the British Isles and the Iberian Peninsula in the west to the Japanese archipelag ...

and in

Morocco Morocco (),, ) officially the Kingdom of Morocco, is the westernmost country in the Maghreb region of North Africa. It overlooks the Mediterranean Sea to the north and the Atlantic Ocean to the west, and has land borders with Algeria ...

, and inhabit

riverine 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 wat ...

ecosystems. Today, most " loaches" are placed in other families (see

below Below may refer to: *Earth * Ground (disambiguation) * Soil * Floor * Bottom (disambiguation) * Less than *Temperatures below freezing * Hell or underworld People with the surname * Ernst von Below (1863–1955), German World War I general * Fr ...

). The family includes about 260 described

species In biology, a species is the basic unit of Taxonomy (biology), classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of ...

. New species are being described regularly.Perdices, A., Bohlen, J., Šlechtová, V. & Doadrio, I. (2016): Molecular Evidence for Multiple Origins of the European Spined Loaches (Teleostei, Cobitidae). ''PLoS ONE, 11 (1): e0144628.''

Description and ecology

The body forms of the Cobitidae tend to be

vermiform Vermiform (ˈvərməˌfôrm) describes something shaped like a worm. The expression is often employed in biology and anatomy to describe usually soft body parts or animals that are more or less tubular or cylindrical. The word root is Latin, ''ve ...

– worm-shaped, long and thin. Most true loaches do not have true

scale Scale or scales may refer to: Mathematics * Scale (descriptive set theory), an object defined on a set of points * Scale (ratio), the ratio of a linear dimension of a model to the corresponding dimension of the original * Scale factor, a number ...

s, and like many other

Cypriniformes Cypriniformes is an order of ray-finned fish, including the carps, minnows, loaches, and relatives. Cypriniformes is an Order within the Superorder Ostariophysi consisting of "Carp-like" Ostariophysins. This order contains 11-12 familie ...

catfish Catfish (or catfishes; order Siluriformes or Nematognathi) are a diverse group of ray-finned fish. Named for their prominent barbels, which resemble a cat's whiskers, catfish range in size and behavior from the three largest species alive, ...

es, they have barbels at their mouths (usually three to six pairs). Some other traits typically found in this family are a small bottom-facing mouth suited to their scavenging

benthic The benthic zone is the ecological region at the lowest level of a body of water such as an ocean, lake, or stream, including the sediment surface and some sub-surface layers. The name comes from ancient Greek, βένθος (bénthos), meaning "t ...

lifestyle, an erectile spine below the eye, and a single row of pharyngeal (throat) teeth. True loaches are mostly

scavenger Scavengers are animals that consume dead organisms that have died from causes other than predation or have been killed by other predators. While scavenging generally refers to carnivores feeding on carrion, it is also a herbivorous feeding b ...

s and are omnivorous, usually not very picky about their food. They may eat aquatic

crustacean Crustaceans (Crustacea, ) form a large, diverse arthropod taxon which includes such animals as decapods, seed shrimp, branchiopods, fish lice, krill, remipedes, isopods, barnacles, copepods, amphipods and mantis shrimp. The crustacean gro ...

insect 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 ...

s, and other small

invertebrate Invertebrates are a paraphyletic group of animals that neither possess nor develop a vertebral column (commonly known as a ''backbone'' or ''spine''), derived from the notochord. This is a grouping including all animals apart from the chordate ...

s, as well as scraps of organic

detritus In biology, detritus () is dead particulate organic material, as distinguished from dissolved organic material. Detritus typically includes the bodies or fragments of bodies of dead organisms, and fecal material. Detritus typically hosts commu ...

. Many live in

eutrophic Eutrophication is the process by which an entire body of water, or parts of it, becomes progressively enriched with minerals and nutrients, particularly nitrogen and phosphorus. It has also been defined as "nutrient-induced increase in phytoplank ...

waters of generally poor quality and feed on tubifex worms and similar

benthos Benthos (), also known as benthon, is the community of organisms that live on, in, or near the bottom of a sea, river, lake, or stream, also known as the benthic zone.atmospheric An atmosphere () is a layer of gas or layers of gases that envelop a planet, and is held in place by the gravity of the planetary body. A planet retains an atmosphere when the gravity is great and the temperature of the atmosphere is low. A s ...

oxygen Oxygen is the chemical element with the symbol O and atomic number 8. It is a member of the chalcogen group in the periodic table, a highly reactive nonmetal, and an oxidizing agent that readily forms oxides with most elements as we ...

. Some species, particularly from the

genera Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial ...

Cobitis ''Cobitis'' is a genus of small freshwater fish in the family Cobitidae from temperate and subtropical Eurasia. It contains the "typical spiny loaches", including the well-known spined loach of Europe. Similar spiny loaches, occurring generally s ...

'' and especially '' Misgurnus'', are sensitive to changing

air pressure Atmospheric pressure, also known as barometric pressure (after the barometer), is the pressure within the atmosphere of Earth. The standard atmosphere (symbol: atm) is a unit of pressure defined as , which is equivalent to 1013.25 millibars, ...

. They change their behavior accordingly, and as these changes in activity are usually followed by a change in weather, they are commonly known as "weather fishes" or "weather loaches". Some Cobitidae have been introduced to foreign lands, where they may pose problems to local wildlife as

invasive species An invasive species otherwise known as an alien is an introduced organism that becomes overpopulated and harms its new environment. Although most introduced species are neutral or beneficial with respect to other species, invasive species adv ...

.''Misgurnus anguillicaudatus'' (fish)
ISSG Global Invasive Species Database Other true loaches, many of them migratory fish, have been seriously affected by

habitat destruction Habitat destruction (also termed habitat loss and habitat reduction) is the process by which a natural habitat becomes incapable of supporting its native species. The organisms that previously inhabited the site are displaced or dead, thereby ...

, chemical

pollution Pollution is the introduction of contaminants into the natural environment that cause adverse change. Pollution can take the form of any substance (solid, liquid, or gas) or energy (such as radioactivity, heat, sound, or light). Pollutants, the ...

, and damming, and are considered

threatened species Threatened species are any species (including animals, plants and fungi) which are vulnerable to endangerment in the near future. Species that are threatened are sometimes characterised by the population dynamics measure of ''critical depensa ...

today. Some migratory species are popular aquarium fish and since they are very hard to raise in captivity,

overfishing Overfishing is the removal of a species of fish (i.e. fishing) from a body of water at a rate greater than that the species can replenish its population naturally (i.e. the overexploitation of the fishery's existing fish stock), resulting in the ...

has seriously depleted once-common stocks in several cases.

Systematics

The other " loaches" used to be included in this family, but nowadays are recognized as well-distinct members of the

order Order, ORDER or Orders may refer to: * Categorization, the process in which ideas and objects are recognized, differentiated, and understood * Heterarchy, a system of organization wherein the elements have the potential to be ranked a number of d ...

. Together with the suckers (Catostomidae), the "loaches" made up the superfamily Cobitoidea. However, the

sucking loach ''Gyrinocheilus'' is the single genus in the family Gyrinocheilidae, a family of small Southeast Asian cypriniform fishes that live in fast-flowing freshwater mountain streams. The species in this genus are commonly called "algae eaters." They ho ...

es (Gyrinocheilidae) were easily recognizable as relatives of the suckers.Nelson, J.S. (2006): ''

Fishes of the World ''Fishes of the World'' by the American Ichthyology, ichthyologist Joseph S. Nelson (1937–2011) is a standard reference for fish systematics. Now in its fifth edition (2016), the work is a comprehensive overview of the diversity and classificat ...

''. John Wiley & Sons, Inc. Eventually, the

hillstream loach The hillstream loaches or river loaches are a family, the Balitoridae, of small fish from South, Southeast and East Asia. The family includes about 202 species. They are sometimes sold as "lizardfish" or (in Germany) "flossensaugers". Many of t ...

es, though more similar to the true loaches than the other two presumed Cobitoidea, were recognized as distinct enough to be better regarded a family in their own right -

Balitoridae The hillstream loaches or river loaches are a family, the Balitoridae, of small fish from South, Southeast and East Asia. The family includes about 202 species. They are sometimes sold as "lizardfish" or (in Germany) "flossensaugers". Many of t ...

. And as it seems the "sucking Cobitoidea" are quite distant indeed, perhaps even markedly closer to the

Cyprinidae Cyprinidae is a family of freshwater fish commonly called the carp or minnow family. It includes the carps, the true minnows, and relatives like the barbs and barbels. Cyprinidae is the largest and most diverse fish family and the largest v ...

, thus the old superfamily Catostomoidea warrants revalidation. Finally, the puzzling

mountain carp Cyprinidae is a family of freshwater fish commonly called the carp or minnow family. It includes the carps, the true minnows, and relatives like the barbs and barbels. Cyprinidae is the largest and most diverse fish family and the largest ve ...

s were most often considered the distinct family Psilorhynchidae in recent times. In a number of systematic schemes, though, they were placed in the Balitoridae (or Balitorinae, when these were included in the Cobitidae). In fact, they seem to be loach-like

carp Carp are various species of oily freshwater fish from the family Cyprinidae, a very large group of fish native to Europe and Asia. While carp is consumed in many parts of the world, they are generally considered an invasive species in parts of ...

s and belong in the

. In 2012,

Maurice Kottelat Maurice Kottelat (born 16 July 1957 in Delémont, Switzerland ...

reviewed the loaches and elevated the former subfamily Botiinae to its own family, Botiidae, and established the family

Serpenticobitidae ''Serpenticobitis'', popularly known as serpent loaches, is a small genus of loaches found in the Mekong River Basin in Southeast Asia. It is the only genus in the family Serpenticobitidae. Species * '' Serpenticobitis cingulata'' T. R. Rober ...

for the genus ''

Serpenticobitis ''Serpenticobitis'', popularly known as serpent loaches, is a small genus of loaches found in the Mekong River Basin in Southeast Asia. It is the only genus in the family Serpenticobitidae. Species * '' Serpenticobitis cingulata'' T. R. Rober ...

''.

Use by humans

Some true loaches are popular as

food fish Food is any substance consumed by an organism for nutritional support. Food is usually of plant, animal, or fungal origin, and contains essential nutrients, such as carbohydrates, fats, proteins, vitamins, or minerals. The substance is inges ...

East Asia East Asia is the eastern region of Asia, which is defined in both geographical and ethno-cultural terms. The modern states of East Asia include China, Japan, Mongolia, North Korea, South Korea, and Taiwan. China, North Korea, South Korea ...

n countries such as Japan. These are of importance in the fisheries or being raised in

aquaculture Aquaculture (less commonly spelled aquiculture), also known as aquafarming, is the controlled cultivation ("farming") of aquatic organisms such as fish, crustaceans, mollusks, algae and other organisms of value such as aquatic plants (e.g. lotus ...

. Small species may occasionally be caught for

bait Bait may refer to: General * Bait (luring substance), bait as a luring substance ** Fishing bait, bait used for fishing Film * ''Bait'' (1950 film), a British crime film by Frank Richardson * ''Bait'' (1954 film), an American noir film by Hu ...

As aquarium fish

Many of the more brightly colored species are popular with

aquarists, so are therefore of importance in the aquarium trade. Some Cobitidae often encountered in aquarium trade include: *

Dojo loach The pond loach (''Misgurnus anguillicaudatus''), also known as the Dojo loach or oriental weatherfish, is a freshwater fish in the loach family Cobitidae. They are native to East Asia but are also popular as an aquarium fish and introduced else ...

, ''Misgurnus anguillicaudatus'' *

Horseface loach ''Acantopsis dialuzona'' is a loach native to the swift, clear streams and rivers of mainland and archipelagic Southeast Asia, from India to Indonesia through the Chao Phraya and Mekong river basins. It can also be found in flooded fields. The ...

, ''Acantopsis choirorhynchus'' * Kuhli loach, ''Pangio kuhlii''

References

{{Taxonbar, from=Q266302 Fish of Europe Fish of Asia Ray-finned fish families

Description and ecology

Systematics

Use by humans

As aquarium fish

See also

References