Aquarium kings – this is the name given to some of the most beautiful aquarium fish on the planet – discus (Symphysodon sp). It belongs to family of cilchlidae and order to Cichliformes. These fish immediately attract the eye due to the extremely unusual, almost round, body shape and enchanting coloration, especially in numerous breeds. The fish were called discus fish for their flattened, disk-like body.
- 1 Discus Fish History
- 2 Appearance
- 3 Habitat
- 4 Discus Fish Views
- 5 Care and Maintenance
- 6 Compatibility
- 7 Diet
- 8 Breeding
Discus Fish History
The genus name consists of two Greek words symphysis – “fused” and odon – “tooth”. And this is due to the peculiarity of the location of the four extreme teeth, located at the junction of the upper and lower jaws, one below the other. The name “discus” appeared a little later. This word in ancient Greece meant a flat throwing projectile for competition.
Discus has a certain specificity of keeping: stable water parameters, high temperature, the need for large volumes for keeping. They can be called extremely sensitive, which discourages many aquarists from keeping these adorable fish. The low immunity of discus is associated with their natural habitat. The water in the Amazon River basin is very soft and acidic and contains a large amount of tannins. In such water, the reproduction of microorganisms is difficult, therefore, discus are not able to properly respond to infections. Thus, discus are recommended for keeping by experienced aquarists who perfectly understand all the processes taking place in the aquarium.
Discus was first described by Australian scientist Johan Natterer during his next expedition to Brazil. It happened in 1833, after a specimen of a previously unknown fish was caught in the Rio Negro River. Johan Jacob Heckel made a great contribution to the study of discus, it was he who proposed the generic name Symphysodon.
The first live discus were introduced to Europe in the middle of the 20th century. Currently, thanks to the mass breeding of fish in special complexes, it is not difficult to buy them practically in any country. But it should be noted that the price of discus remains one of the highest. Especially when it comes to a rare color variation.
The body of the discus has a disc-like shape and is very strongly compressed from the sides, up to the fact that when observing the fish from the side of the caudal fin, you can see two eyes protruding from the sides of the head. These eyes are large and are located on a small head. The fins can be transparent or have colored spots in the same color as the body. The caudal fin is fan-shaped; the dorsal and anal fins run from head to tail. The pelvic fins are elongated. In adult male discus, a distinctly protruding forehead can be observed. The color is extremely varied and depends on the specific species, but it is always effective. It can change depending on the state of the fish: colored stripes can appear or disappear all over the body. In an aquarium, discus can grow up to 25-30 cm.
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Discus fish is native to the rivers of South America. They are found in the Amazon Basin. Therefore, discus can be found in countries such as Brazil, Colombia, Venezuela and Peru.
The biotopes of the Amazon Basin are very interesting and can undergo significant changes. In December, the rainy season begins, which leads to flooding of rivers, as a result of which huge areas are flooded. Floods bring a lot of turbidity, and the previously crystal clear waters become like a swamp. After the end of the long rains, the water level drops, it becomes transparent again. Quiet backwaters appear everywhere, in which the water acquires a dark color (“black water”). In such isolated areas, the water is extremely soft and acidic. It is in such conditions that discus live in the wild. They prefer to stay closer to the coast, live in thickets of bushes. The bottom in such reservoirs is a thick layer of decaying leaf litter.
Most of the life and spawning of fish take place among the roots of coastal vegetation. It is worth noting that it is very rare to find discus fish in large rivers; they prefer small streams and tributaries. As a result of this isolation, local color populations of discus fish have arisen, and we can observe a magnificent variety of colors of these amazing fish.
Discus Fish Views
The taxonomy of discus has undergone certain changes during the study of the life of fish. Initially, all discus were attributed to the same species, considering the differences in color to be only color variations. But a more detailed examination of the features of these fish led to the identification of three species within the genus Symphysodon.
Red Discus Fish (Symphysodon discus)
This species of discus was the first to appear in hobbyist aquariums. In honor of the scientist who first described this species, it is often called the Heckel discus.
They live in South America, in the Amazon basin: in particular, in the Rio Negro, Rio Branco and other rivers. They prefer water rich in humic substances, the so-called “black water”. The soil in natural biotopes is sandy with a large number of dying leaves.
The shape of the body is standard, disc-shaped, flattened from the sides. The iris of the eyes is bright red. The body color of the Heckel discus ranges from reddish yellow to brown. Longitudinal wavy blue lines cross almost the entire body of the fish, except for the chest and the middle of the body. There are nine vertical dark stripes on both sides of the flattened body, the first, fifth and ninth stripes are most pronounced (brighter and wider). The color of discus may vary depending on the condition of the fish.
If the fish is agitated, the vertical lines practically disappear, but the blue ones become much brighter. In stressful situations or with poor content, everything happens exactly the opposite: the blue lines fade, and the vertical ones become more contrasting. When the situation is very advanced, almost complete disc discoloration can be observed. In nature, it grows up to 20 cm, in aquariums the size usually does not exceed 10-15 cm. Sexual dimorphism is weakly expressed. The natural diet is based on zoo and phytoplankton, as well as detritus during dry periods.
Green Discus Fish (Symphysodon Tarzoo)
Despite the fact that the main body color of the fish is brownish-yellow, when examining a specimen of discus fish caught in nature with a reflection of a blue sky, the scales appear greenish. The fish received a specific epithet in honor of the Colombian company from the city of Leticia, specializing in the export of fish. It was in its vicinity that Symphysodon tarzoo was caught and described. It should be noted that this group of discus received the status of a species relatively recently – in 2006, based on DNA analysis.
The green discus lives in the Amazon River basin (Peru, Colombia, Brazil). They prefer black water. They live near the coast among sunken trees and dying leaf litter.
The iris is bright red. Longitudinal wavy lines of turquoise color run along the entire body and dorsal fin of the green discus. A wide black stripe runs along the dorsal fin. Morphologically, this type of discus differs from others in the presence of reddish dots on the body and fins, which appear in fish at the age of six months. Sexual dimorphism is not pronounced. The average size of a green discus in an aquarium is 13 cm.
Blue Discus Fish (Symphysodon Aequifasciatus)
The specific epithet consists of two Latin words: aequus – “equal” and fascia – belt. The name reflects the main morphological difference from other species – the presence of vertical stripes of the same width and intensity on the sides of the body. Large schooling fish. For maintenance, an aquarium with a volume of 250 liters or more is recommended. It is necessary to strictly maintain optimal water parameters (temperature, acidity) and prevent the accumulation of nitrogen metabolism products.
Discus is inhabited in the basins of the Amazon and Rio Negro rivers. They prefer clear water. The length reaches 15 cm. The head and mouth are small. The body is disc-shaped, with a wavy pattern on it. The background color of the fish varies from brownish-yellow to red. Horizontal stripes are blue or greenish. A wide dark stripe runs along the dorsal and anal fin in a semicircle. Body coloration may vary depending on the condition of the fish. Distinguishing a female discus from a male is quite problematic.
There are several subspecies of Symphysodon aequifasciatus with a characteristic coloration – brown and blue discus. Determining the exact type of discus in an aquarium is almost impossible due to the fact that many years of work of breeders have led to the appearance of a large number of color variations. Sexual dimorphism in these fish is not pronounced.
Care and Maintenance
To keep discus, first of all, you need a spacious aquarium. The minimum volume for a small school of fish is 250 liters, but ideally this should be an aquarium of 400 liters or more. The height of the water column is desirable about 50 cm, since discus is a relatively tall fish in an adult state. When keeping discus fish, it is very important to provide peace of mind to pets. Fish are very shy and constant stress factors can lead to illness and even death. It is not recommended to set up an aquarium with discus in walk-through areas or near sources of strong sounds.
There are two main approaches to the interior of an aquarium when keeping discus. Some aquarists prefer the classic version – a herbal aquarium with soil and dense thickets of plants.
Others believe that discus do not need an additional background, and it is better to keep them in an aquarium without soil, plants and decorations. The latter point of view is more practical and is associated with the fact that, firstly, it is difficult to find plants that can withstand the optimal temperature for discus (27-30 ° C). Secondly, any dying organic matter in the aquarium is a potential source of nitrogenous compounds, to the content of which discus are very sensitive.
On the other hand, a herbal tank with discus looks much more spectacular, and live plants help maintain the biological balance in the aquarium. The most important thing is thorough care, supply of carbon dioxide, high-quality lighting.
Discus do not tolerate any fluctuations in water parameters. The more stable the environment, the less likely these fish will get sick. Discus are extremely thermophilic: the optimum temperature is 27-30 ° C. The water should be acidic and soft, close to that in nature. pH = 5.5 – 6.5, hardness – 1 to 12 ° dGH.
The aquarium should be provided with high-quality filtration (powerful external filter or even several) and aeration. An increase in the content of nitrates in water above 25 g / l must not be allowed. Discus are very sensitive to the concentration of nitrogenous compounds, and exceeding the norm can cause stress. A weekly change of up to ¼ of the aquarium water is required. Although there is a recommendation that it is advisable to do a daily water change of 10-20%. In this case, each aquarist decides for himself how best to proceed. The main thing is to regularly test the water for basic parameters and prevent their sudden jumps. With good care, discus can live in an aquarium for 10 to 18 years.
The main problem when choosing neighbors for discus is water parameters, first of all, temperature. Few fish are able to feel comfortable at water temperatures around 30 ° C. It is also necessary to take into account the fact that discus fish are extremely slow fish, and when kept with very active relatives, they can remain without food. Most aquarists agree that it is best to keep discus fish in a species aquarium in a flock of 6 or more individuals. Thanks to the large number of colored breeding forms of discus, even when kept alone, an amazing variety of colors can be created in the aquarium. However, if there is a desire to combine discus fish with other fish, then you should pay attention to small haracin ( neons , tetras), small freshwater rays, dwarf South American cichlids ( apistogram , etc.).
In addition to optimal water parameters, discus fish also need proper and balanced nutrition. Inappropriate feeding can cause health problems in discus, especially inflammation of the gastrointestinal tract. Most aquarists believe that live and frozen foods are the best type of food for discus fish: brine shrimp, bloodworms, tubifex. Feeding with homemade beef heart-based minced meat is very popular. Such feeds have several disadvantages – it takes time to prepare, it is difficult to balance the ration of discus. In addition, the use of such feed can lead to a rapid deterioration in water quality.
Tetra Discus Dry Food
Especially for discus lovers, Tetra has developed a series of foods that are ideal for all discus species, ensuring health, longevity and activity. Tetra Discus dry food is available in several varieties, so it will be easy for the aquarist to find the kind of food that his pets will happily eat.
- Tetra Discus is the most famous and beloved food for more than one generation of aquarists. With its shape, color and composition it fully meets the specific needs of discus. Contains natural substances that enhance the color of fish and stabilized vitamin C for increased disease resistance. Small red granules, which slowly sink to the bottom, are well eaten by discus. The high digestibility of the components allows you to reduce waste and maintain optimal water quality for a longer time.
- Tetra Discus Energy is specially formulated to reduce stress and improve immunity in discus. Specially selected high quality ingredients support fish health. L-carnitine, which is part of the granules, affects the metabolism and promotes better lipid absorption, which gives the fish an additional supply of energy. Especially recommended during or after stressful situations (illness, water change, exhibition, spawning).
- Tetra Discus Color is a slow sinking pellet that is rich in high performance color enhancers to maintain the beautiful coloration of red discus species.
- Tetra Discus Pro is an innovative food in the form of multi-chips, prepared using low-temperature technology, which allows you to preserve even more nutrients and vitamins. The food is well absorbed by the discus and helps to reduce the level of water pollution from waste. Natural color enhancers guarantee full color, beautiful and rich coloration.
It is necessary to feed discus fish at least 2-3 times a day in such an amount that can be eaten by fish in a few minutes. It is advisable to remove uneaten food residues from the aquarium using a siphon.
Like other members of the family, discus breeds in pairs. They are monogamous and are coupled for life.
Sexual dimorphism in fish is not pronounced. Distinguishing a male from a female is possible for sure only during the spawning period. However, experienced hobbyists note that adult males have steeper foreheads and thick lips. Sexual maturity occurs at the age of 1.5 years.
It is not difficult to understand when the fish are ready to spawn: they begin to prepare a place for their nest – they clean the stones and leaves of plants in order to lay eggs on them in the future. At this time, they need to be transplanted into a spawning aquarium with plants and hiding places. It is desirable that the length of the aquarium be at least one meter and the volume of 100 liters or more. The lights should be dimmed and the spawning tank should be supplied with oxygen at all times. The water used is very soft 2-3 ° dGH. The temperature needs to be raised a few degrees above that in the general aquarium.
The spawn is deposited on the walls of the aquarium, shelters, plant leaves. On average, one female can lay up to 200 eggs.
Discus have a pronounced parental instinct. The eggs, and then the fry, are guarded by a pair or one of the parents. During the caviar care period, the producers should not be disturbed, any potential threat could lead to the caviar eating by the discus. The first larvae are born after three days. The method of feeding the fry is also unusual in discus fish. For the first two weeks, juveniles feed on a special secret secreted on the skin of their parents. Both the female and the male are involved in this process. As soon as one parent runs out of mucus, the second one comes to the rescue.
Once this process is over, producers can be transferred to a common aquarium and self-fed. At a young age, discus are rather unremarkable – they have a pale coloration, which becomes brighter from the age of 3 months.
Different types of discus are capable of interbreeding with each other, which allows for a large number of color variations.