All You Need to Know About Freshwater Fish Species

If all of the water on Earth was put into a five-liter bottle, the amount of freshwater we humans can access is only a tablespoon. In other words, the amount of accessible freshwater is less than 1 percent of the world’s total water supply. The availability of sufficient and high-quality water is also the basic condition for the future of freshwater ecosystems. Freshwater fish live in these ecosystems. Freshwater fish, which are quite a few in number compared to marine fish, still have an important place in amateur and commercial fishing. Let’s learn a little more about freshwater fish!

Freshwater fish are fish that live in waters where the water is potable and not brackish or salty. Among the best known are species such as carp, catfish, eel, trout, and pike. Unlike marine fish, freshwater fish produce large amounts of dilute urea with low salt content. That is, gills can absorb salts from freshwater. This enables them to live in freshwater. Freshwater resources can be formed in nature by the ecological cycle or can be obtained by accumulation and distillation in man-made ponds and cisterns. Freshwater fish, especially trout, are farmed in man-made freshwater ponds.

General Features of Most Common Freshwater Fish

Common Carp

The family that has the most species among fish families in the world is the Cyprinidae family. Carp has spread around the world through transport and vaccination. Carp fish, which is an economically important species in temperate climate regions, is a fish species that is resistant to cold as well as being warm. They are also very resistant to pollution and water temperature differences. Carp has a wide heat tolerance. They require little oxygen and prefers turbid water. They show good development above 20 ° C. They can survive when exposed to 1 ° C water temperature and sudden temperature changes. Carp fish grow at 5% salinity and pH between 5-9.

Omnivores are fed (both vegetable and animal foods). Their nutrients are benthic aquatic animals, plankton, plant parts, and plant residues. They eat small aquatic creatures at the bottom with the mud and throws the mud back. Therefore, they make holes in the mud. It has also been observed that large carp eat some small fish. They lay their eggs randomly in the vegetation in shallow waters at 15 degrees and above in the spring. At least three male fish follow the egg-laying female and fertilize the eggs. The offspring hatched a week later are fed closed in their own yellow pouch for a while. Later, the vulnerable juvenile carp are frequently targeted by fish such as Perch.

Carp has more specific eating habits than other anglers. The carp feeds on all kinds of food such as plants, mollusks, crustaceans, eggs, or fry of other fish, algae, worms. It is a cautiously fed fish. When he sees a sudden change or bait in his environment, he acts cautiously and does not jump into that food immediately. He has a hunt that needs patience and time. Commercial, amateur hunting, and breeding are important. Although the oldest individual recorded is 20 years old, it is known that carp live much longer. It can be more than 47 years of life and weigh more than 75 pounds. World record carp is a 34 Kg fish caught in Lac de St Cassien-France in 1987.

Mirror Carp

It is very similar in appearance to the scaly carp. It differs from scaly carp in appearance with its scattered and sparse scale structure. The recorded maximum length is 120 cm, average length 45- 65 cm, maximum weight (European) 42 kg 637 g, average weight 2.7 -6.8 kg, Life expectancy is between 9-45 years. However, there are those who have 45+ years of life on record. Its habitat, feeding, and breeding characters are similar to the scaly carp. Its cultivation is done. It is also an important fish in sporty fishery.

Leather Carp

It is a type of carp with almost no scales on its skin. It shows similar character to scaly and mirror carp and grows slower than them.

Salmon

It can be up to 150 cm in height and 47 kg in weight. The oldest known individual is 13 years old. It is bottom-swimmer (benthopelagic) and upward-nomadic (anadrome). It enters the sea, brackish water, and freshwater. Commercial fishing and breeding are very important. Young individuals migrate to the sea after 1-6 years in freshwater. They spend 1-4 years at sea. Those who reach sexual maturity return to the sea after spawning in the freshwater they were born. However, most of them die after ovulation. Growth in freshwater is slow. They grow faster in the sea. The differences between Salmon and Rock Trout are as follows:

Salmon’s tail fork is concave, in rock trout convex or nearly straight.
Salmon’s tail is thinner, rock trout has a thicker tail.
There are no black spots below the lateral line of the salmon.
Salmon’s eye, in front of the mandible plate line.
The head of the salmon is more pointed, the rock trout is more rounded and blunt.

Pike-Perch

Swimmer (pelagic), life depth range 2 – 30 m (usually 2-3 m), potamodromous (migratory). It makes short migrations for spawning. The first reaching sexual maturity is 28-46 cm. Maximum length is 1 m, average height is 50 cm, maximum weight recorded is 20 kg, age: 17 years. It is of great economic importance because of the deliciousness of its meat. However, artificial production cannot be made under culture conditions, since its nutrition is completely based on other living fish. However, stocks can be converted into a more economical form by grafting them into natural lakes where other fish are abundant.

For this purpose, inland waters can be made more efficient by inoculating some natural lakes and dams with the aforementioned fish. However, the inoculation of these fish into our natural waters may also have bad results. Because, as a result of the consumption of other forms in the lake, a break in the food chain may occur, thus the balance of nature may be disturbed. The body is thin and long and covered with small ctenoid scales. Its head is more pointed and its length is 1/4 of the standard body length. The posterior end of the upper jaw extends to the vertical line lowered from the posterior edge of the eye. There are well-developed, pointed canines in the mouth.

The top of the gill covers are usually bare and there is no spike-shaped extension at the end of the gill cover. Especially in males, the dorsal area between the head and the first dorsal fin is slightly humped. The tail fin is less indented and the tip of the lobes is round. The overall color of the body is bright white, the back is gray-green, the sides and abdomen are silver, white. On the sides of the body and especially in the area above the sideline, there are brown-brown spots varying in number between 10-12. There are brown spots in regular order on the membranes between the rays of the dorsal and caudal fins.

This species can generally survive in fresh and less salty waters. Freshwater forms are found in the lower basins of streams and especially in large lakes. It has a form that lives in saltwater in the Caspian and Azov seas. It is an ambush hunter. Although it is very predatory like pike fish, the fish it can swallow are smaller. The main food of this predatory fish is especially carp type fish. The spawning period is between April and June. Sexual maturation occurs at the age of 3-4. The eggs are glued by the female fish on the stones and plant roots on the gravel-sandy ground. A female fish can give up to 200,000 eggs with a diameter of 1-1.5 mm per kg of body weight. Commercial and amateur hunting value is high.

Silver Bream

Silver bream is demersal (living at the bottom), potamodromous (migrating within the river itself or from a lake) fish. Lives more than 10 years. The maximum recorded length is 36 cm. its average length is 20 cm. The maximum recorded weight is 1 Kg. Between May and July, it spawns near roots, the submerged plants, and even the lower shore of shallow pebbles. It feeds on benthic invertebrates generally at night. It has no commercial hunting value.

Bullhead

It is found in cold, clear, and fast-flowing waters of medium-sized rivers, small streams, and on gravelly or rocky shores of cold lakes. It is demersal. The recorded maximum length is 18 cm, the average length is 10 cm, and its maximum age is 10 years. Their food is benthic invertebrates, fish eggs, and larvae. It reaches the first sexual maturity between 2-4 years. It spawns in March-April. It lays its eggs on pebbly bottoms. A single male can fertilize many female eggs. Male fish protect the eggs during incubation.

European Chub

The European chub lives in sandy and slow-flowing lowland rivers, in large lakes, and streams along the banks of these rivers. While the rivers cool, they migrate to the lakes. Maximum recorded height is 60 cm (male), average common height: 30 cm, maximum weight: 8 kg, maximum age: 22 years. The first sexual maturity length is 7-30 cm. The age of sexual maturity is 4-6 years for males and 3-4 years for females. It lays eggs multiple times throughout the year. Minors feed on aquatic and terrestrial materials, adults feed on fish. It forms fertile hybrids with pearlfish. It is a popular fish in amateur angling.

Northern Pike

It is a river-nomadic fish close to the bottom (demersal) and spreads between 0-30 m. It has high economic value. It is indirect polar and found in freshwaters. The male can be 137 cm, 28 kg, and the female 150 cm and 35 kg. It lives up to 30 years. The length to reach sexual maturity is 25-63 cm. It has been infused into the waters of many different regions and has caused significant ecological problems. Usually wanders alone. It mostly feeds on fish, and it is a cannibal.

Wels Catfish

It is a bottom-swimmer (benthopelagic). The life depth range is 0-30 m. The age of first access to sexual maturity is 2-3 years, the length of first access to sexual maturity is 86-108 cm. The maximum length is 500 cm, the average length is 300 cm, the maximum published weight is 306 kg and the maximum reported age is 80 years. Spawning begins in April. Catfish wait for eggs until the larvae hatch from the egg. Its color is gray, petrol green, depending on the water it lives in; Its belly and sides are dirty yellows, there are large black spots on its back, sometimes this black color can dominate the general color of the fish. It has no scales, its skin is slippery.

Its eyes are small compared to its body, like most animals that hunt at night. There are three pairs of sensory organs (mustaches), two of which are longer in the upper jaw and four shorter in the lower jaw. The sensory organs in the form of whiskers in their jaws are well developed, and they feel even the tiniest vibrations in the water with a sensory line extending from the head to the body. The vibrations caused by the movements in the water reach the sensory organs of the catfish just under the skin through the pores in the skin, the channel where the sensory organs under the skin are located along the fish.

In addition, catfish have a very developed sense of smell. Armed with these senses, catfish can easily hunt. They feed on small fish, crayfish, worms, frogs, and water birds. It swallows its prey whole. It is usually fed at night. It has been observed that it rarely hunts during the day. The mouth of the catfish is very large and there are no incisors, rows on its lower and upper jaws, with rows of stinging inward teeth that will serve more to hold the prey. Although it has a structure that is not suitable for feeding on the bottom due to its slightly long lower jaw, it is also fed from the bottom.

It has a tendency to swallow anything. It has often been observed that shoes, cans, dead cats, or dogs came out of the stomach of the fish caught. It is also known to attack birds or poultry swimming in the water. Commercial and amateur hunting value is high.

It is a mysterious fish. It lives in both freshwater and sea. There are differences between a baby eel and an adult eel as if they were two different species. When there is enough moisture, it can survive on land for a long time. Eel larvae were found in the Sargasso Sea, in the western Atlantic Ocean. However, the existence of adults and how they ovulate has not been witnessed. Therefore, it is assumed that they die after ovulation. It is a demersal fish that is low-migratory (catadrome). It is found at depths of 0-700 meters. It is one of the bony fishes, the female is a maximum of 150 cm in length and 4-6 kg in weight, with an average of 600 gr-2 kg. The highest age determined is 85 years.

It is economically important. Access to sexual maturity is 70-90 cm in female fish and the age of access is 5-10 years. It grows in freshwater and spawns in late winter and early spring between Bermuda and the Bahamas in the part of the western Atlantic Ocean called the Sargasso Sea. This is the only area in a particular location where this species is directed to perform a breeding stage. Leptocephaly maggots (larvae) are transported to the shores of Europe by the Gulf current. After this 6,000-kilometer-long journey, which lasted 1 to 3 years, the larvae reached a length of 7 centimeters and entered the delta areas. Before they enter the freshwater, they transform into small eels called “glass eels”.

After spending 6-12 years in freshwater, the males of the fish undergo a change in shape and enter sexual maturity. Mature individuals do not feed during migration. The bellies of the individuals who have turned to spawn are silvery shiny, their eyes are enlarged and their skin is dark-colored. They feed on all kinds of food and cadavers. They live on the floor, under stones, or in the mud.

The Most Abundant Freshwater Fish: Carp

Carp (Cyprinus carpio) is a freshwater fish that gives its name to the carp family (Cyprinidae). It is found in lakes and slow-flowing streams. It is a long-bodied bottom fish that feeds on worms, insect larvae, and plants. There are those that are 1.5 meters tall and weigh 35 kg. Lifespan can be up to 40-50 years. A freshwater fish from the carp family, with a long and large body. Its homeland is Asia. It was produced after the 12th century in the fresh waters of Europe and America. It has an important place in artificial fishing.

Carp adapt to water at any temperature. It is found in waters between 3-30 ° C. In extreme cold, they hibernate collectively, buried in mud. They can freeze without dying in the winter. They can swim against the water current. It squeezes its tail between its jaws, and when it releases, it can overcome the cascades by jumping 3-5 meters, dividing like a spring.

Carp (Cyprinus carpio) fish found throughout the freshwater lakes in the world is a favorite of amateur and sport anglers. In its environment, it generally feeds on maggots, insects, and plants at the bottom. It is very enjoyable to hunt carp, which can be caught by different methods of hunting. Especially carp weighing 5 kg and above give us unforgettable moments. People think that carp is easy prey, however, hunting carp is an art, it takes patience and discipline. If you are thinking of hunting carp, you should devote a few days to yourself, not just one day.

When we arrive at the hunting ground, we must observe the hunting spot and make a good choice. It will be very logical to determine the point where we will put our fishing rods and bait. We make corn, pellet feeds, or a mixture with the dough we prepare. We can make use of specially produced feeding equipment while feeding. To give an example of these, we can use bait boats, bait rockets, or remotely controlled bait boats using more advanced technology.

Depending on the ground conditions in the lake where we hunt, we can hunt with bottom fishing rods or buoys. Since the carp fish, which can reach gigantic sizes, love silence, it is useful to stay as far away as possible after shooting our fishing rods to the water. Carp flock and are sensitive to odor, attractants can be used when preparing the dough. Common Carp and Mirrored Carp are the most common types of carp. Carp or a different type of fish that we caught in recreational fishing should be left to its natural environment as soon as possible and with the least damage so that sustainability can be achieved.

As with other fish, the most crucial answer to the question of how to catch carp is hidden in determining where it is found. However, the existence of the carp in your area is not enough for it to be hunted. Carp is not fed in every environment where it is present. One of the important conditions is that the place where you throw your fishing line is close to a place where carp can be stored. The deficit of a reed bed, branches of trees that have entered the water, between aquatic plants that cover certain parts of the water surface, where trees used to be in artificial lakes (dams, ponds, etc.), where there were rotten roots and tree trunks underwater, are ideal hiding places.

In such places, it feels safer to feed, but the carp, which takes the bait, will immediately want to return to the hiding place and digest it there. For this reason, your fishing rod will also absorb these relationships (grass, reed, root, etc.). This determines how to tackle the second stage of hunting. The most enjoyable, productive hunting grounds with the highest probability of trophy hunting for carp are relatively large dams established for electricity generation. Carp starts to use all its power to breed and grow in a large and stagnant lake, not by looking for stagnant environments between the currents, as before, in such places, that is, in an environment that suddenly turns into a lake, and is abundant in large sizes.

The key to success in hunting these waters is finding the right landform. So what is this landform? The most beautiful carp places are the small peninsulas on the coast, especially the little capes with elongated bays to the right or left. You should throw your fishing line to the right or left of the part of the peninsula that lies in the water about 10-15 degrees on these noses or peninsulas. You should decide whether to throw right or left on the side of the peninsula that contains the deep bay.

Hunting/Production of Freshwater Fish Species

Freshwater resources are indispensable for the continuity of living life. Human history is full of examples of great civilizations founded near or around freshwater springs: Egypt, Mesopotamia, Sumerian, Inca, and Aztecs. Since lakes are calmer waters among freshwater resources than rivers, their ecology rapidly deteriorates as a result of human activities.

Food chain destruction (eutrophication), acidification, salinization, heavy metal and other toxic contamination, disruption of the natural water regime (water use, agriculture, energy, and global warming) can be listed among the major threats faced by lakes as a result of human activities. The history of people’s curiosity towards seas, lakes, rivers, and the creatures that sustain their lives in these environments and their efforts to get to know them closely corresponds to centuries before Christ. Scientific handling takes place in Europe in the 1700s.

Reasons such as the development of industry, population growth, and environmental pollution have resulted in the decrease in fish species not only in the seas but also in lakes all over the world, and the risk of extinction of some species. The last situation in the species of freshwater fish is that 20 percent of them are in danger of extinction compared to the previous years.

Efficient use of available resources is becoming increasingly necessary as an effect of the increasing population all over the world. Food production from aquatic ecosystems that make up three-quarters of the world is seen as one of the most important resources. In the last 10 years, there has not been a significant increase in fishing production by fishing method worldwide and it is accepted that sustainable production will not exceed 100 million tons. On the other hand, there is a continuous increase in aquaculture and aquaculture production.

Freshwater production is generally carried out in two ways: hunting and aquaculture. While the share of fishing in total production has decreased in recent years, the amount of production made by aquaculture is increasing rapidly. The most important reason for this is that the amount of product that can be obtained by fishing from the seas cannot be increased more. While it is estimated that the amount of fish that can be caught for sustainable fishery reached the highest level, it is seen from the increasing production amounts from year to year that aquaculture has become increasingly important worldwide.

Looking at the amount of fishing in inland waters worldwide, it was 11,271,565 tons in 2010, and 11,635,500 tons in 2016. Considering the data, while the total hunting amount was 89.099.961 tons in 2010, this rate was 90.923.545 tons in 2016. Considering the growth rate of the world population, it is seen that there is a stagnation rather than a decrease in the amount of hunting in the world between 2010 and 2016.

Since the 1980s, when the world fishing production was relatively stagnant, the total sea fishing was 81.2 million tons in 2015 and 79.3 million tons in 2016. It is reported that the anchovy (Engraulis ringens) hunt, which was hunted by Peru and Chile and showed a highly volatile course, decreased 1.1 million tons due to the effect of Hurricane El Nino. In addition to the effects of climatic factors, factors such as quota differences applied by countries, prohibitions and regulations, restriction of fishing gear are also present in the decrease in the amount of hunting.

Between 2010 and 2016, the world aquaculture volume in marine and inland waters increased by an average of 4 million tons per year. The amount of aquaculture production, which was 59.1 million tons in 2010, reached 80 million tons in 2016, an increase of 33% compared to 2010. The most important reason for this situation is the increasing food demand. The need for food increased by an average of 3.2% per year, doubling the growth rate of the world population of 1.6%. Therefore, the steady growth in aquaculture does not seem surprising. Other factors that affect this growth; urbanization and increasing income level.

Freshwater Aquarium Fish Species

Freshwater aquarium fish are the types of fish that live in rivers, lakes, and streams found in many countries of the world and have been introduced to the aquarium hobby world and have the potential to live in the aquarium ecosystem. Freshwater aquarium fish are divided into species among themselves. There are fish species that can live in harmony with each other as well as fish species that cannot live with each other.

Today, countries that have reached advanced levels in the import of aquarium fish both produce and import the fish they catch from lakes and rivers, which are their natural environments, to the whole world. We can list the freshwater aquarium fish species as follows:

Live Breeding Fish
Cichlids
Labyrinths
Catfish
Carp-like Fish

Live-Breeding Fish

Fish varieties that spend their incubation period in their abdomen without taking their eggs out of the uterus are called live-breeding fish. Live breeding animals that adapt well to aquarium conditions are among the most preferred aquarium fish group worldwide. The homeland of live breeding fish is fresh and shallow waters from Central America to Brazil, including Barbados and Trinidad. From here it was taken to various countries and produced in aquariums.

Cichlids

Another type of fish that is most preferred in the aquarium hobby world is Cichlids. It is a fish species with thousands of different species, whose homeland is Africa, America, and Brazil. Each subspecies has its own unique color, pattern, and muscle structure. Included in aggressive and semi-aggressive fish species. Almost all African gums live in one of three large lakes in East Africa; Fish living in the Lake Malawi, Lake Victoria, and Lake Tanganyika basin make up the population of African Cichlids. The most widely fed type of cichlid in the world is the Malawi cichlid from Lake Malawi.

Labyrinths

Labyrinth fish also have two organs called labyrinths located on the upper part of their gills, near the back of their eyes. They get their names from these organs. The labyrinth organ has a structure with many folds right above the gills. These respiratory organs consist of three or more flat ossicles on the fourth of the four-gill arcs lined up behind the gill cover, fusing into a chamber by forming folds and attaching to the fourth-gill arc.

Cat Fish

It got its name from having a cat-like mustache. It is possible to see one of the catfish family in many rivers and lakes. They can easily eat anything that can fit in their mouth. The catfish have many species among themselves and the most favorite catfish of the aquarium hobby is the red tail catfish.

Carp-like Fish

It is a type of fish whose shape resembles a carp, has a thinner mouth than its head, and can feed on all kinds of living things in its natural environment. Although these fish are very preferred in the aquarium community, there are many hobbyists who feed these fish without knowing that they belong to the carp family. Nowadays, the first fish that comes to mind when it comes to carp feeding in the aquarium is koi and goldfish.