The
tench or
doctor fish (
Tinca tinca) is a
freshwaterFreshwater is naturally occurring water on the surface such as bogs, ponds, lakes, rivers and streams, and underground in aquifers and underground rivers. Freshwater is characterized by having low concentrations of dissolved salts...
and
brackish waterBrackish water is water that has more salinity than fresh water, but not as much as seawater. It may result from mixing of seawater with fresh water, as in estuaries, or it may occur in brackish fossil aquifers. The word comes from the Middle Dutch root "brak," meaning "salten" or "salty"...
fishA fish is any aquatic vertebrate animal that is typically ectothermic , covered with scales, and equipped with two sets of paired fins and several unpaired fins...
of the
cyprinidThe family Cyprinidae, from the Ancient Greek kyprînos , consists of the carps, the true minnows, and their relatives . Commonly called the carp family or the minnow family, its members are also known as cyprinids...
(commonly called 'carp') family found throughout
EurasiaEurasia is a large landmass covering about 52,990,000 km
2 or about 10.6% of the Earth's surface...
from
Western EuropeWestern Europe is the collection of countries in the westernmost region of Europe, though this definition is context-dependent and carries cultural and political connotations. One definition describes Western Europe as a cultural entity—the region lying west of Central Europe...
including the
British IslesThe British Isles are a group of islands off the northwest coast of continental Europe that include Great Britain, Ireland and numerous smaller islands. There are two sovereign states located on the islands: the United Kingdom of Great Britain and Northern Ireland, and Ireland...
east into
AsiaAsia is the world's largest and most populous continent, located in the eastern and northern hemispheres. It covers 8.6% of the earth's total surface area and with approximately 4 billion people, it hosts 60% of the world's current human population.Asia is traditionally defined as part of the...
as far as the
ObThe Ob River , also Obi, is a major river in western Siberia, Russia. It is the country's fourth longest. The Ob River also has the longest estuary in the world.-Names:...
and
Yenisei RiverYenisei is the greatest river system flowing to the Arctic Ocean, and at 5,539 km is the fifth longest river in the world. Rising in Mongolia, it follows a northerly course to the Yenisei Gulf in the Kara Sea, draining a large part of central Siberia, the longest stream following the...
s. It is also found in
Lake BaikalLake Baikal is the world's second most voluminous lake, after the Caspian Sea. It is the most voluminous freshwater lake in the world with an average depth of 744.4 m and contains a total of roughly 20 percent of the world's surface fresh water...
. It normally inhabits slow-moving freshwater habitats, particularly lakes and lowland rivers.
The tench is most often found in still waters with a
clayClay is a naturally occurring material composed primarily of fine-grained minerals, which show plasticity through a variable range of water content, and which can be hardened when dried and/or fired...
or
mudMud is a liquid or semi-liquid mixture of water and some combination of soil, silt, and clay. Ancient mud deposits harden over geological time to form sedimentary rock such as siltstone or solid, mudrock lutites. When geological deposits of mud are formed in estuaries the resultant layers are...
dy
substrateIn biology a substrate is the surface a plant or animal lives upon. The substrate can include biotic or abiotic materials. For example, encrusting algae that lives on a rock can be substrate for another animal that lives above the algae on the rock. See also substrate .-External links:*...
and abundant vegetation.
The
tench or
doctor fish (
Tinca tinca) is a
freshwaterFreshwater is naturally occurring water on the surface such as bogs, ponds, lakes, rivers and streams, and underground in aquifers and underground rivers. Freshwater is characterized by having low concentrations of dissolved salts...
and
brackish waterBrackish water is water that has more salinity than fresh water, but not as much as seawater. It may result from mixing of seawater with fresh water, as in estuaries, or it may occur in brackish fossil aquifers. The word comes from the Middle Dutch root "brak," meaning "salten" or "salty"...
fishA fish is any aquatic vertebrate animal that is typically ectothermic , covered with scales, and equipped with two sets of paired fins and several unpaired fins...
of the
cyprinidThe family Cyprinidae, from the Ancient Greek kyprînos , consists of the carps, the true minnows, and their relatives . Commonly called the carp family or the minnow family, its members are also known as cyprinids...
(commonly called 'carp') family found throughout
EurasiaEurasia is a large landmass covering about 52,990,000 km
2 or about 10.6% of the Earth's surface...
from
Western EuropeWestern Europe is the collection of countries in the westernmost region of Europe, though this definition is context-dependent and carries cultural and political connotations. One definition describes Western Europe as a cultural entity—the region lying west of Central Europe...
including the
British IslesThe British Isles are a group of islands off the northwest coast of continental Europe that include Great Britain, Ireland and numerous smaller islands. There are two sovereign states located on the islands: the United Kingdom of Great Britain and Northern Ireland, and Ireland...
east into
AsiaAsia is the world's largest and most populous continent, located in the eastern and northern hemispheres. It covers 8.6% of the earth's total surface area and with approximately 4 billion people, it hosts 60% of the world's current human population.Asia is traditionally defined as part of the...
as far as the
ObThe Ob River , also Obi, is a major river in western Siberia, Russia. It is the country's fourth longest. The Ob River also has the longest estuary in the world.-Names:...
and
Yenisei RiverYenisei is the greatest river system flowing to the Arctic Ocean, and at 5,539 km is the fifth longest river in the world. Rising in Mongolia, it follows a northerly course to the Yenisei Gulf in the Kara Sea, draining a large part of central Siberia, the longest stream following the...
s. It is also found in
Lake BaikalLake Baikal is the world's second most voluminous lake, after the Caspian Sea. It is the most voluminous freshwater lake in the world with an average depth of 744.4 m and contains a total of roughly 20 percent of the world's surface fresh water...
. It normally inhabits slow-moving freshwater habitats, particularly lakes and lowland rivers.
Ecology
The tench is most often found in still waters with a
clayClay is a naturally occurring material composed primarily of fine-grained minerals, which show plasticity through a variable range of water content, and which can be hardened when dried and/or fired...
or
mudMud is a liquid or semi-liquid mixture of water and some combination of soil, silt, and clay. Ancient mud deposits harden over geological time to form sedimentary rock such as siltstone or solid, mudrock lutites. When geological deposits of mud are formed in estuaries the resultant layers are...
dy
substrateIn biology a substrate is the surface a plant or animal lives upon. The substrate can include biotic or abiotic materials. For example, encrusting algae that lives on a rock can be substrate for another animal that lives above the algae on the rock. See also substrate .-External links:*...
and abundant vegetation. This species is rare in clear waters across stony ground, and is absent altogether from fast-flowing streams. It tolerates water with a low
oxygenOxygen Oxygen Oxygen (acid, literally "sharp", from the taste of acids) and -γενής (-genēs) (producer, literally begetter) is the element with atomic number 8 and represented by the symbol O...
concentration, even being found in waters where the
carpCarp is a common name for various species of an oily freshwater fish of the family Cyprinidae, a very large group of fish native to Europe and Asia. Some consider all cyprinid fishes carp, and the family Cyprinidae itself is often known as the carp family...
cannot survive.
Tench feed mostly at night on algae and benthic invertebrates of various kinds that they root up from the bottom.
Breeding takes place in shallow water usually among aquatic plants where the sticky green eggs can be deposited. Spawning usually occurs in summer, and as many as three hundred thousand eggs may be produced. Growth is rapid, and fish may reach a weight of 0.11
kgThe kilogram is the base unit of mass in the International System of Units .[The spelling kilogram is the modern spelling used by the International Bureau of Weights and Measures , the U.S...]
(0.25
lbThe pound or pound-mass is a unit of mass used in the imperial, United States customary and other systems of measurement...
) within the first year.
Morphology
Tench have a stocky, carp-like shape, olive-green skin, darker above and almost golden below. The caudal fin is square in shape. The other fins are distinctly rounded in shape. The mouth is rather narrow and provided at each corner with a very small
barbelA barbel on a fish is a slender, whiskerlike tactile organ near the mouth. Fish that have barbels include the catfish, the carp, the goatfish, sturgeon, and some species of shark...
. Maximum size is 70 cm, though most specimens are very much smaller. The eyes are small and red-orange in colour. Sexual dimorphism is weak, limited to the adult females having a more convex ventral profile when compared with males. Males may also possess a very thick and flattened outer ray to the ventral fins.
The tench has very small scales, which are deeply imbedded in a thick skin, making it as slippery as an
eelTrue eels are an order of fish, which consists of four suborders, 19 families, 110 genera and approximately 600 species. Most eels are predators...
.
FolkloreFolklore is the body of expressive culture, including stories, music, dance, legends, oral history, proverbs, jokes, popular beliefs, customs, and so forth within a particular population comprising the traditions of that culture, subculture, or group. It is also the set of practices through which...
has it that this slime cured any sick fish that rubbed against it, and from this belief arose the name
doctor fish.
Golden tench
An artificially-bred variety of tench called the
golden tench or
schlei is a popular
ornamental fishFishkeeping is a popular hobby concerned with keeping fish in a home aquarium or garden pond.- Types of fishkeeping :The hobby can be broadly divided into three specific disciplines, freshwater, brackish, and marine fishkeeping....
for ponds. This form varies in colour from pale gold through to red, and some fish have have black or red spots on the flanks and fins. Though somewhat similar to the
goldfishGoldfish are small ornamental freshwater fish that are commonly kept as pets. Goldfish were one of the earliest breed of fish to be domesticated and are still one of the most commonly kept fish in aquariums and outdoor water gardens.Goldfish were originally domesticated from the Prussian carp ,...
, because these fish have such small scales, the golden quality is rather different. This variety is said to have been originally bred in
SilesiaSilesia is a historical region of Central Europe located mostly in present-day Poland, with parts in the Czech Republic and Germany....
.
Economic significance
Tench are edible and considered to have a fine flavour, working well in recipes that would otherwise call for carp. They are an important target for coarse
anglerAngler may refer to:* A fisherman* One who practices the fishing method of angling*Angler * The angler, Lophius piscatorius, a goosefish* More generally, any anglerfish in the order Lophiiformes...
s and are also used as
fodderIn agriculture, fodder or animal feed is any foodstuff that is used specifically to feed domesticated livestock such as cattle, goats, sheep, horses, chickens and pigs. Most animal feed is from plants but some is of animal origin...
for predatory species such as
bassThe sunfishes are a family of freshwater ray-finned fish belonging to the order Perciformes. The type genus is Centrarchus . The family's 27 species includes many fishes familiar to North Americans, including the rock bass, largemouth bass, bluegill, pumpkinseed, and crappies...
. Tench, particularly golden tench, are also kept as ornamental fish in ponds and less frequently aquaria.
Angling
Large tench may be found in gravel pits or deep, slow-moving waters with a clayey or silty bottom and lots of aquatic vegetation. They take a variety of
baitBait is any substance used to attract prey, e.g. in a mousetrap.-Fishing:The term is especially used with regard to catching fish. Traditionally, nightcrawlers, insects, and smaller fish have been used for this purpose. Fishermen have also begun using plastic bait and, more recently, electronic...
s but are "nibblers" and are difficult to hook. Fish over 1 kg (2 lb) in weight are very strong fighters when caught on a rod.