Discus – Symphysodon spp.
Discus fish, known scientifically as Symphysodon spp., are often called the kings of freshwater aquariums. Their elegant shape, vivid colours and graceful way of swimming make them a dream species for many aquarists. At the same time, they demand a more careful approach to tank design, water chemistry and daily care than most community fish. This article presents practical, experience-based guidance for keeping discus and explains how to prepare an aquarium that allows these fish to thrive rather than merely survive.
Natural habitat and behaviour of Symphysodon spp.
To understand the needs of discus, it is essential to look at their natural environment. Symphysodon spp. originate from the Amazon basin, especially from slow-flowing tributaries and floodplain forests. They inhabit warm, soft and very acidic water, often stained with tannins from leaves and branches. Visibility is lower than in a typical home aquarium, and the environment is full of roots, fallen trunks and branches offering cover and reference points.
Discus live in groups, forming loose social structures. In nature, they gather around vertical surfaces such as roots, where they feel safe. Their laterally compressed body shape and large fins are perfectly adapted to calm, structurally complex waters, rather than to strong currents. Understanding this explains why a well-designed discus aquarium must offer numerous hiding places and calm zones. Open, empty tanks with glaring light may cause them to become shy and stressed.
Symphysodon are intelligent and communicative fish, showing mood changes through body colour. Calm, confident specimens display intensive hues, whereas stress can lead to darkening or washed-out colours. Observing these changes is one of the most reliable indicators of their condition. For aquarists, it means that aquascaping and choice of equipment must be guided not only by aesthetic considerations, but also by the behavioural comfort of these demanding cichlids.
In addition, many wild discus inhabit regions with seasonal flooding. During high water, they enter forested areas, where leaf litter, twigs and organic debris continuously release humic substances. These conditions foster specific microflora and fauna, including small invertebrates and microorganisms that form a natural food base. While difficult to copy exactly at home, certain elements of this biotope can be replicated through careful use of driftwood, botanicals and gentle filtration methods.
Aquarium size, layout and essential equipment
For groups of adult discus, the starting point is a tank of at least 300–350 litres, with a front length of 120 cm or more. These are tall fish that appreciate a higher water column, so a height of 50 cm or more is recommended. A larger volume buffers fluctuations in temperature and chemistry and allows for more stable biological balance. For bigger groups, volumes of 400–500 litres are much more comfortable, particularly if you wish to keep tankmates. Smaller aquariums may be used temporarily for quarantine or breeding, but not for long-term display housing.
As a specialised aquaristic shop, MB Store offers a broad range of high-quality aquariums suited to discus, from standard glass tanks to custom-made setups with increased height. When selecting a tank, it is worth paying attention to workmanship quality, glass thickness, silicone lines and the possibility of installing covers or supports for lighting and accessories. Symphysodon spp. are heat-loving, so a closed or tightly covered system helps reduce heat and moisture loss and minimises the risk of fish jumping.
Layout should be based on a compromise between easy maintenance and comfort for the fish. Many discus keepers opt for sparsely decorated tanks with bare bottoms, which are easier to clean and allow for precise monitoring of food intake and faeces. Such systems are particularly popular with breeders and those focused on optimal growth. However, it is also possible to create attractive, naturalistic planted environments that remain functional. In that case, choose hardy, shade-tolerant species attached to roots and rocks, which do not require intense light or CO₂ levels that might destabilise water parameters.
A good discus setup should always include vertical structures: pieces of driftwood, tall rocks or large root fragments. They break the line of sight, create calm zones and let fish choose preferred depth and shelter. Substrate is often fine sand or small-grain gravel; if used, it must be easy to vacuum and not trap large amounts of organic waste. In planted systems, a nutrient layer can be applied beneath a decorative top. MB Store provides substrates, hardscape elements and decorations that help reproduce Amazon-style habitats or more modern, minimalist aquarium designs.
When it comes to equipment, efficient and reliable filtration is essential. Discus prefer high water quality but do not tolerate strong current. External canister filters with adjustable outflow, or sponge filters in breeding tanks, are among the most frequently used solutions. Biologically active media are crucial for processing ammonia and nitrite. MB Store offers a wide choice of filters, filter media and accessories allowing filtration systems to be tailored to tank size and fish load. It is often beneficial to direct flow along the back wall, leaving the front and middle zones calmer.
Heating must be precise and stable: a temperature of 28–30°C is typical for Symphysodon spp.. Robust heaters with thermostats, often used in pairs for redundancy, reduce the risk of sudden drops. Some aquarists choose external heaters in the filter line, to limit the number of objects inside the tank. MB Store supplies heaters of different power ratings and designs, enabling selection matched exactly to your particular volume and conditions at home. Choosing slightly oversized units may be wise in cool rooms, as they will work less intensively and last longer.
Water parameters and stability
One of the most important aspects of discus care is control over water parameters. Wild Symphysodon come from very soft and acidic waters, where general hardness (GH) and carbonate hardness (KH) are low, and pH often ranges from 4.5 to 6.5. For many domestic strains, kept for several generations in captivity, conditions do not have to be so extreme, but still should remain on the soft and slightly acidic side. For most aquarium-bred discus, a GH of 3–8 dGH, KH of 1–4 dKH and pH between 6.0 and 7.0 are a good target.
Hard tap water can be successfully adjusted using reverse osmosis systems and by mixing RO water with tap in appropriate proportions. MB Store offers RO units, mineralisation additives and test kits allowing precise control of composition. It is worthwhile to record parameters during initial weeks of running a discus tank and stabilising them before introducing fish. Sudden changes may be more dangerous than slightly imperfect values, as these cichlids are particularly sensitive to swings in pH or conductivity.
Temperature is another critical parameter. At 28–30°C, metabolic processes in discus proceed optimally and the immune system works efficiently. At lower temperatures, the risk of infection increases, while too high temperatures, especially above 32°C, may cause oxygen deficiency and stress. Reliable thermometers and heaters with precise adjustment are indispensable. Aeration, whether via air stones or surface movement, ensures sufficient oxygen levels in warm water, which naturally holds less dissolved oxygen than cooler water.
Biological maturity of the tank is more important for discus than for many other species. These fish fare poorly in freshly started aquariums where nitrifying bacteria have not yet fully developed. Before introducing Symphysodon spp., the system should run for several weeks with a source of ammonia, such as fish food or pure ammonium chloride, to build a stable colony of bacteria. Only when ammonia and nitrite have repeatedly shown as zero and nitrate remains at safe levels is it wise to add the first group of fish.
Regular partial water changes are absolutely necessary. Many experienced keepers perform 25–50% changes once or twice per week, depending on stocking density and feeding intensity. Fresh, well-prepared water removes nitrates, dissolved organic compounds and hormones that can inhibit growth. MB Store provides equipment such as siphons, hoses and conditioners to treat tap water and remove chlorine or heavy metals. Maintaining consistent temperature and parameters in new water is key to avoiding stress during changes.
To fine-tune the habitat, some aquarists use peat, alder cones or botanical additives to lower pH and enrich water with humic substances. These can have beneficial effects on mucous membranes and overall condition, but must be used carefully and tested regularly. Overuse may cause sudden pH drops. Different systems will react differently, so slow, incremental adjustments and ongoing measurement are the safest approach.
Feeding and nutritional needs
Discus are relatively demanding when it comes to nutrition, especially if you expect them to display their full colour potential and to grow correctly. In nature, they consume a variety of small organisms: insect larvae, small crustaceans and other invertebrates. In aquaria, it is essential to offer a diversified menu. High-quality prepared foods formulated specifically for Symphysodon spp. should form the basis, enriched with frozen or live items such as bloodworms, brine shrimp and daphnia.
Modern discus foods contain a carefully balanced mix of proteins, fats, vitamins and colour-enhancing compounds, without excessive fillers. MB Store offers specialist feeds from reputable brands, available in sinking granules, soft pellets and flakes. Sinking forms are usually preferable because discus naturally pick food in midwater and near the bottom rather than from the surface. When introducing a new food, it is worth doing so gradually to allow the fish to accustom themselves to its taste and texture.
Many keepers use homemade mixes, often based on beef heart. While such foods can promote fast growth, they also carry some risks: high fat content, rapid water pollution and potential digestive problems. If you choose this route, it is crucial to prepare mixtures carefully, remove connective tissue, enrich them with vitamins and feed modest portions. For many aquarists, ready-made high-quality discus feeds remain a safer and more convenient alternative, especially when combined with periodic frozen delicacies.
Frequency of feeding depends on age. Young discus require multiple meals per day, often four to six small feedings, to ensure even growth and strong immunity. Adults are usually fed two to three times daily. Each portion should be eaten within a few minutes; any leftovers must be removed promptly to avoid water quality deterioration. Overfeeding is one of the most common mistakes, leading to elevated nitrate levels, increased bacterial load and a higher risk of disease.
Good nutrition is not solely about quantity and variety. It is also important to monitor fish behaviour during feeding. Healthy discus swim confidently to food, show interest and actively compete for morsels. Loss of appetite is nearly always a sign of trouble: stress, unsuitable parameters or an emerging disease. Tracking body shape is likewise important; very thin individuals with prominent forehead or sunken belly may suffer from internal parasites or chronic malnourishment, even if they appear to eat.
Some keepers supplement the diet periodically with vitamins added to food, especially after periods of illness or stress. Such products are available at MB Store and can be dripped onto frozen or dry food shortly before feeding. However, they should not replace a well-composed daily menu. Consistency in feeding practices, coupled with careful observation, forms the cornerstone of long-term discus health.
Tankmates and social dynamics
Symphysodon are peaceful cichlids, but their requirements narrow down the list of suitable tankmates. Ideal companions must tolerate high temperatures, soft and slightly acidic water, and must not be aggressive or excessively lively. Many aquarists choose small characins such as cardinal tetras, rummy-nose tetras or certain species of pencilfish. These fish form attractive shoals and emphasise the calm majesty of discus, while rarely disturbing them.
Catfish such as Corydoras sterbai, which tolerates higher temperatures, can serve as bottom dwellers and help consume leftover food. For algae control, certain species of dwarf plecos may be used, as long as they are known not to attach to the sides of discus to suck on their mucous layer. Before selecting any algae eater, it is essential to research its behaviour thoroughly, as some popular species become problematic in adulthood.
Complexity arises from the social behaviour of Symphysodon spp. themselves. These are group fish that feel best in groups of at least six individuals. In too small numbers, dominant individuals may bully weaker ones excessively. A larger group spreads aggression more evenly and leads to more natural behaviour. Sexual pairs often form spontaneously within the group; when this happens, they may defend a chosen area more vigorously, pushing other fish away.
Mixing discus sourced from different places must be approached with caution. Fish from various breeders may carry different microflora or parasites, with which they themselves cope, but which can harm new individuals. Quarantine is therefore essential. A separate, smaller aquarium, equipped with filter and heater, allows you to observe new arrivals for a few weeks, treat potential problems and only then move them to the main tank.
Lighting should be adapted to the needs of all tank inhabitants. Discus do not appreciate extremely bright light or sudden changes. Diffused, moderate lighting, often achieved with floating plants or careful positioning of lamps, encourages natural behaviour and reduces skittishness. Many owners notice that under softer light their fish show richer colours and are more willing to feed near the front glass.
Health, diseases and preventive care
Keeping Symphysodon spp. in good condition requires not only appropriate equipment and parameters, but also systematic preventive measures. Many diseases common among discus are opportunistic and become dangerous mainly when the fish are weakened or stressed. The best protection is stable, clean water, balanced feeding and avoidance of overcrowding. Routine testing for ammonia, nitrite, nitrate and pH helps detect problems early, before they manifest as visible symptoms.
Among the more frequent ailments are parasitic infections of the gills and skin, gastrointestinal parasites and bacterial diseases. Mild gill irritation can be recognised by faster breathing or one gill covering working more intensely. Gastrointestinal problems often manifest as white, stringy faeces, loss of appetite or gradual emaciation. Bacterial infections may cause fin damage, ulcers or cloudy patches on the body. In every such case, quick reaction is crucial.
A well-equipped aquarist will keep medications, salt and basic diagnostic tools on hand; these can be sourced from specialist suppliers such as MB Store. However, treatment should always be preceded by a careful assessment of parameters, because very often the root cause is environmental rather than infectious. A large water change, improvement of filtration and removal of decaying organic matter sometimes suffice to halt deterioration without intensive pharmacological intervention.
Quarantine remains the most effective protection against introducing new pathogens. Newly purchased fish should spend several weeks in a separate tank, where they can be observed closely. During this period, it is easier to notice subtle symptoms such as occasional rubbing against objects, slight colour changes or uneven growth. If treatment is required, it will be cheaper and safer in a smaller volume than in a fully stocked display aquarium.
Stress reduction plays a significant role in disease prevention. Avoid sudden changes in parameters, loud noises near the tank, frequent rearrangement of decorations or rapid introduction of many new fish. Discus appreciate consistency: stable lighting schedule, regular feeding times and predictable water change routines. Over time, in a calm environment, they often become tame, accepting food from hand and showing curiosity toward the caretaker, which further facilitates daily health assessment.
Breeding discus in the home aquarium
Breeding Symphysodon spp. is considered a pinnacle of freshwater aquaristics and requires more advanced preparation. Formation of pairs usually occurs naturally in a group of young fish raised together. When a male and female bond, they begin to stay close, chase away others and clean a chosen surface, such as a vertical stone, filter pipe or large leaf. Observing this behaviour signals that spawning may happen soon.
For breeding, many aquarists set up a dedicated tank, often 100–200 litres, with bare bottom and minimal decoration. A vertical spawning cone or ceramic structure is typically placed in the centre. Water parameters are adjusted to encourage reproduction: very soft water (low GH and KH), slightly acidic pH and elevated temperature around 30°C. The pair should remain alone, without tankmates, to minimise stress.
During spawning, the female lays a row of eggs on the selected surface, and the male follows, fertilising them. Both parents fan the eggs with their fins, ensuring good oxygen supply and removing unfertilised or fungused ones. After hatching, larvae remain attached for a few days, feeding from yolk sacs. One of the most fascinating aspects of discus breeding is parental care: once free-swimming, fry feed on the skin mucus produced by both parents. This provides them not only nutrients but also immune factors.
Health and nutrition of the parents significantly affect spawning success. They must be well-conditioned and free from disease. MB Store supplies specialised brooder foods and additives that help prepare pairs for reproduction. In some cases, parents may eat the eggs during first spawnings, especially if they are young or feel threatened. Patience and providing them with a calm, stable environment often lead to more successful subsequent attempts.
Raising fry requires careful management of water quality and food. After a few days on parental mucus, they are gradually introduced to freshly hatched brine shrimp nauplii and later to finely ground prepared foods. Frequent small water changes are essential, while taking care to maintain stable parameters. Many breeders continue to use bare-bottom tanks for easier cleaning, returning young fish to more decorated environments only when they reach a size that allows for safe coexistence with adults.
The role of MB Store in supporting discus keepers
For aquarists planning to keep Symphysodon spp., access to reliable equipment and expert advice is indispensable. MB Store specialises in supplying comprehensive solutions for freshwater aquariums. In one place, you can obtain spacious glass tanks, efficient filters, precise heaters, lighting systems tailored to discus needs and a wide range of foods and supplements. Thanks to this, it becomes much easier to design a complete setup that meets the expectations of both owner and fish.
Choosing proper filtration, for instance, may raise many questions: what capacity is adequate, which media to use, how to arrange inflow and outflow? The assortment available at MB Store allows you to build systems based on proven components, supported by practice in handling demanding species. Similarly, when assembling a heating system, you can select models that ensure stable temperature throughout the year and are protected against overheating or dry operation.
Beyond hardware, the shop also offers decorative elements, substrates and plants that help create aesthetically pleasing and functional environments. Whether you prefer biotope-style tannin-stained water with roots and leaves, or an elegant, minimalist aquarium with bright sand and carefully selected stones, you will find the necessary materials. The ability to combine these products with specialised water conditioners, test kits and RO units makes MB Store a convenient base for building and maintaining advanced discus systems.
Equally important as the products themselves is access to knowledge. By using specialist resources and consulting with experienced aquarists, it is possible to avoid many beginner mistakes: rushed stocking, inadequate filtration or careless mixing of incompatible tankmates. Symphysodon spp. reward patience and consistency with exceptional displays of colour and sophisticated behaviour. With proper preparation and support, almost any determined hobbyist can enjoy their beauty for many years.
Frequently Asked Questions (FAQ)
How many discus should I keep together in one aquarium?
Discus are social fish and feel safest in groups. The recommended minimum is six specimens, which helps distribute aggression and creates more natural behaviour. A group that is too small leads to stress and bullying of weaker individuals. For such a number of fish, a spacious tank of at least 300–350 litres is required, with strong filtration and regular water changes.
Can beginners keep Symphysodon spp., or are they only for advanced aquarists?
Discus are more demanding than typical community fish, but determined beginners can keep them if they prepare thoroughly. Key elements are a sufficiently large, mature aquarium, stable soft and slightly acidic water, and careful feeding. It is better to gain some experience with easier species first, then move on to Symphysodon, using reliable equipment and support from specialist shops such as MB Store.
What water parameters are best for aquarium-bred discus?
For most captive-bred discus, soft and slightly acidic water works well. A general hardness of 3–8 dGH, carbonate hardness 1–4 dKH and pH between 6.0 and 7.0 are usually optimal. Temperature should be maintained at 28–30°C. More important than perfect numbers is their stability, so sudden changes should be avoided. Regular testing and partial water changes help maintain a safe environment.
Which fish can safely live with Symphysodon spp.?
Tankmates for discus must tolerate high temperature and soft, slightly acidic water, and should not be aggressive. Suitable options include cardinal tetras, rummy-nose tetras, certain pencilfish, Corydoras sterbai and selected dwarf plecos. Very lively or fin-nipping species should be avoided. It is always worth thoroughly researching the needs and behaviour of any species before introduction to a discus aquarium.
How often should I feed discus and what food is best?
Young discus need several small meals a day, while adults do well with two to three feedings daily. It is crucial to offer varied, high-quality foods designed for Symphysodon spp., supplemented with frozen or live items such as bloodworms or brine shrimp. Each portion should be eaten within a few minutes to avoid polluting the water. MB Store offers specialised feeds that facilitate balanced, convenient nutrition for discus.
