The discus is a cute and colorful fish that inhabits the Amazon River. It has a rounded, slightly flattened body on the sides. Quite a large fish, adults can reach a length of 20 centimeters. For their bright coloration and calm disposition, they are loved by aquarists around the world. And this is understandable, because you rarely see more beautiful fish. When kept in an aquarium, they do not cause trouble, and please their owner.
Origin of the species and description
Photo: Discus
Symphysodon discus (discus) to genus Symphysodon. Class ray-finned fish, perch-like order, cichlid family. This species was discovered back in 1904. It combines several variations of subspecies of Symphysodon discus Heckell.
Video: Discus
In the course of Dr. Askelrod's research, there was a publication in the Tropical Fish Hobbyist, which provided a taxomy of the genus Symphysodon. In this publication, the species Symphysodon aequifasciata was first identified as an independent species. The term aequifasciata is taken from the Latin meaning striped, and it refers to the peculiar evenly striped color of the fish of this species. This species has vertical dark stripes located throughout the body of the fish, in fish of the subspecies «Heckel» all stripes are expressed in the same way.
Thus, in this edition, Dr. Axelrod identified the following taxonomy of this species:
- Symphysodon discus Heckell, 1840 includes discus Heckel discovered in 1840;
- Symphysodon aequifasciata Pellegrin.
This species includes:
- amber-green discus;
- blue discus;
- brown discus.
Later, the same scientist spoke about the incompleteness of his own research in this area, in 1981, in the same edition, he published a new, more detailed taxonomy of this species. The subspecies Symphysodon discus Heckel includes S. discus Heckel, and S. discus willischwartzi Burgess. Symphysodon aequifasciata Pellegri includes S. aequifasciata haraldi Schultz, S. aequifasciata Pellegrin, and S. aequifasciata axelrodi Schultz.
Later in 2006, scientists from Switzerland proposed to systematize this genus into three species:
- Symphysodon discus Heckell it includes discus Heckel;
- Symphysodon aequifasciata Pellegrin this species includes equally striped discus aequifasciata Pelegrin;
- S. tanzoo Lyons, this species includes the red-spotted green discus S. t. tanzoo Lyons.
Appearance and Features
Photo: Discus Fish
Symphysodon discus have a round, disc-shaped body. The body is strongly flattened on the sides. The head of the fish is small. In males, the frontal part of the head is especially distinguished. On the head are two slightly protruding eyes. The fins on the back and the anal fin are low, but rather long. The fish has a beautiful, fan-shaped tail. The fins located on the belly of the fish are elongated. Often the fins are transparent, long they have bright spots. The spots are predominantly the same color as the color of the body. In the color of fish of this species, a pattern of 9 vertical stripes is noted. Discus colors can be varied – bright blue, gold, green, golden fish.
Interesting fact: Discus can change their own color, depending on their own condition. Stripes of different colors may appear on the body of the fish, or vice versa, stripes of different colors may disappear. If the fish is nervous or excited, the vertical lines on the fish can practically disappear, while the horizontal ones, on the contrary, become brighter.
During the breeding season, males can see a pointed seed tap. In female fish of this species, a cone-shaped ovipositor is formed during spawning. Sexual dimorphism in this species of fish is not pronounced. In captivity, the size of an adult individual reaches 20-25 centimeters, larger individuals of this species are also found in nature.
The life span of discus in the natural environment is from 10 to 16 years, however, fish live less in captivity. This is due to constant stress, and forever favorable living conditions. In addition, complementary foods also shorten the age of fish. However, they do better in their natural environment. Discus have a calm disposition. They are slow. Move slowly. They live and swim in small flocks.
Where does the discus live?
Photo: Discus in the Amazon
The habitat of these bright fish, these are rivers located in South America. Most often, flocks of discus can be found in the Amazon River. Also, this species is found in the waters of Colombia, Venezuela, Brazil and Peru.
The Amazon River has different biotypes, which vary greatly depending on the time of year. In winter, during the rainy season, the rivers overflow. Which leads to flooding of large areas.
During floods, rivers are heavily polluted due to the leaves of trees and plants that are flooded. By spring, the water subsides, forming many streams and small, isolated reservoirs. The water becomes dark. In isolated places, the river becomes like swamps, but in spring the water clears up. In such areas, the water is soft and has a high acidity. Water has the lowest electrical conductivity. Discus live in such conditions.
Usually discus choose a place to live, located as close to the coast as possible. They live in flooded bushes. At the bottom there is a rather thick layer of foliage. Discus hide in the flooded grass and among the roots of plants, spawning of fish of this species also takes place there. These fish do not live in large rivers and clear water, they settle more and more often in small, well-heated channels with diffused light. Thanks to this isolation, certain color populations were created, which we can now observe.
And also thanks to this isolation, the habits of schooling fish began to be noted. In one flock, you can see up to a couple of hundred individuals. In fast-flowing rivers, discus are almost impossible to find. They choose quiet and isolated places.
What does a discus eat?
Photo: Discus in nature
Basic Diet Discus in wildlife consists of:
- plants, flowers, seeds and leaves. Plant fruits. (they make up about 45% of the total fish diet);
- invertebrates living in water (approximately 6% of the diet);
- Chironimidae larvae;
- various arthropods, mainly small spiders that live on the ground and wood.
During the dry season when there is no access to plants and arthropods.
The diet of this fish species is as follows:
- the basis of the diet is detritus (organic matter consisting of the remains of various invertebrates, decomposed bones and plant particles. As well as secretions of various organisms that are suspended in water in the form of particles, or settle to the bottom of the reservoir);
- algae of all kinds;
- aquatic invertebrates and plant material;
- various small crustaceans, shrimp remains, small crustaceans.
When keeping fish in captivity it is quite difficult to recreate such a diet of fish, the diet of fish kept in captivity usually includes:
- frozen artemia salina; >dry food;
- bloodworms (bloodworm) mosquito larvae.
Veal liver, shrimp, squid, spinach leaves are often used for feeding. Some aquarists provide fresh vegetables. In addition, it is recommended to give purchased vitamin complexes from time to time.
Now you know how to keep discus in an aquarium. Let's see how fish live in the wild.
Character and lifestyle features
Photo: Discus
Discus are relatively quiet fish. They have a calm nature. In nature, they live in isolated flocks. One such flock can number up to several hundred individuals. There is usually no conflict in the pack, except that the males may quarrel over the female. Sometimes during the breeding process, the male and female may quarrel among themselves. If at that moment they have caviar already laid, they can eat it.
In nature, fish live in small warm reservoirs and streams with diffused light, warm water and many places to hide. These fish are afraid of loud sounds and sudden movements. Stress has a bad effect on fish, they change their color, feel bad. Near Symphysodon discus in nature, you can find fish such as Cyclids of various genera, knifefish, catfish, rays and piranhas.
In terms of neighborhood with other fish, discus are not aggressive, there is no struggle for territory. And many other fish will not live in the territory occupied by discus due to the fact that the water is too warm and soft there. In ordinary life, fish live in flocks. Such flocks are usually not clearly formed. During spawning, fish are divided into pairs consisting of a male and a female. Fish spawning takes place in secluded places among the flooded roots of shrubs and various plants.
In captivity, these fish are often kept in large isolated aquariums. Discus of all kinds are safe enough for neighbors, but other fish cannot get along with them because of their thermophilicity. It is undesirable to plant discus together with aggressive angelfish and other fish, otherwise the angelfish may begin to terrorize them and cut off the fins of calm discus.
Social structure and reproduction
Photo: Blue Discus
Discus fish have a fairly developed social structure. They are schooling fish. They come out to spawn in formed pairs. Fish start spawning from the second year of life. Spawning occurs in secluded places among snags, plant roots. To prepare for spawning fish prepare a place for the game. They clean a stone, a snag or a leaf of a plant.
Discus usually mate in the dark. Usually there are practically no mating games. Caviar, which usually contains about two hundred eggs, is placed on a cleaned subostat. After the fertilization process is completed, the male takes care of the game. Discus have a developed parental instinct. Caviar and fry, the couple carefully guards their offspring.
Interesting fact: Although discus take care of their offspring, under any stress while looking after fish eggs, producers can eat them themselves.
The fry begin to hatch from the eggs after three days. During the period until the fry have grown stronger, the parents are with them and feed them. Discus fry have a pale, unremarkable coloration. The coloring becomes bright closer to the third month of life of the fry. Reproduction of fish in an aquarium occurs in special conditions. Water for fish during spawning should be at a temperature of about 30 degrees.
It is important that there are no other fish in the aquarium, often a pair for spawning is planted in another aquarium without soil, but in which there is a place for spawning. Algae, stones, various grottoes. The fry kept in the aquarium starting from the 6th day are fed with live dust. At the same time, part of the water is replaced daily. After the parents finish feeding the fry, they are removed.
Natural enemies of discus
Photo: Yellow Discus
Discus have many natural enemies. Discus enemy number — one is the electric eel. He loves to eat these fish. Also, the enemies are mainly larger and more aggressive fish. Due to their calm nature and some slowness, these fish may suffer from other inhabitants. They are very slow eaters, and other fish may steal food from discus, although other fish do not like to settle in such conditions as discus live.
Fish such as locaria and various types of catfish love to feast on the milky mucus secreted by discus. During sucking, they cause injury to the discus, from which the fish can die. They also do not like being around angelfish and other aggressive fish that can harm them and break off their fins.
In addition to fish that do not often settle in discus habitats, these beautiful fish are also threatened by diseases and bad environmental conditions. In the natural environment, discus practically do not get sick, but in an aquarium, these beautiful fish can become ill.
The main diseases of discus kept in captivity are:
- hexamitosis. Characterized by refusal to eat. Change in color of fecal matter. Treat with an increase in the temperature of the water in the aquarium;
- a disease caused by the bacterium Flexibacter columnaris when the fish is affected by these bacteria, there is a decrease in appetite, difficulty breathing and darkening of the color. Treat the disease with a solution of Levomycetin.
Another natural enemy of discus is changing environmental conditions. Discus are very heat-loving fish, they cannot stand strong temperature fluctuations. They need warm, clean water with high softness and acidity in natural conditions, fish can move to more comfortable conditions, in an aquarium with a sharp increase or decrease in temperature, fish of this species may experience a shock, and they may simply die.
Population and species status
Photo: Discus fish
Because of their beauty, these fish are forced to suffer. And from year to year their population is declining. Since these fish are especially loved by aquarists around the world, they are often caught out of their natural habitat. In this case, many fish die. To date, the species Symphysodon discus is listed in the Red Book. Also, the population of this species is negatively affected by climate change, pollution of the reservoirs in which the fish live. The species has been declared endangered due to overfishing. Catching fish of this species is prohibited by law in many countries.
An interesting fact: For the first few weeks, the fry feed on a secret that is secreted by the skin of their parents. This mucus is secreted on the skin of both manufacturers. As soon as one of the parents runs out of mucus, the second parent appears nearby and feeds the offspring. Sometimes, under bad conditions, mucus is not secreted from the fish of the parents, then the offspring dies. Feeding fry artificially at this age is not possible.
The discus that are now on sale are fish born in captivity. In many countries, discus are bred in artificial reservoirs, aquariums and in reservoirs of various nature reserves. At the moment, in Brazil, on the banks of the Amazon, the Tumukumak Conservation Park is being created, where there will be many rivers, reservoirs and waterfalls, which will become a protected natural area.
Discus Conservation
Photo: Red Book Discus
As mentioned earlier, discus are listed in the international Red Book, and this species has the status of & # 171; endangered species, due to frequent capture & # 187;. Catching discus of any species is prohibited by the law of Brazil, Belgium, South America.
Today, a conservation area is being developed on the banks of the Amazon River – the Tumukumake Reserve Park. In this park, all reservoirs that fall into the park are protected. Catching in them is prohibited, there are no enterprises and roads near the park. And discus live in these reservoirs. In addition, in Japan and some other countries, the species Symphysodon discus is grown in artificially created conditions.
The fish currently on the market are bred by experienced aquarists. In aquariums, this species successfully breeds and lives for about ten years, provided that all the necessary requirements for them are met. Captive-bred fish have a brighter neon color and are easier to adapt to aquarium conditions than their wild relatives.
In order to preserve these beautiful fish, a person needs to take care of nature. Stop the crazy fishing, and do not pollute water bodies, build treatment facilities at enterprises so that emissions do not get into the water.
Discus is the undisputed king of aquariums, people are very fond of them for their neon bright color. Seeing a flock of discus in a pond or aquarium takes our breath away from what beauty Mother Nature gives us. But man, unfortunately, for the sake of profit, almost exterminated these lovely creatures. Let's be more careful with nature and what it gives us, and save these beautiful fish for future generations to see.
