Did you know that discus fish (lat. Symphysodon) are often called the ‘king of freshwater tanks’? Their bright, almost regal appearance and graceful swimming style truly make them stand out among other species. Large, vibrant, and with a fascinating range of colors, from deep reds to iridescent blues, it’s no wonder aquarists admire them. But the title of ‘king’ goes beyond just their looks—discus fish carry themselves with a calm, stately demeanor, moving leisurely through the water as though they rule their aquatic kingdom.
Aquarists are drawn to discus not just for their beauty but also for their peaceful and social nature, which can transform any tank into a serene, eye-catching display. However, it’s important to remember that discus fish require careful attention to water quality and temperature, making them more suitable for experienced hobbyists. A common mistake many make is underestimating their care needs, which can lead to stress and poor health. With the right setup and dedication, however, they truly reign supreme in freshwater aquariums.
Contents
Habitat in the wild
They belong to the vast and diverse cichlid family (Cichlidae)? Within this family, discus fall under the genus Symphysodon, with three recognized wild species:
- Symphysodon aequifasciatus Pellegrin, 1904 (blue or brown discus): The most widespread wild species, known for its range of natural color variations.
- Symphysodon discus Heckel, 1840 (red or Heckel discus): Highly prized among hobbyists for its distinct red hues and bold patterning.
- Symphysodon tarzoo E. Lyons, 1959 (green discus): Rarely seen in aquariums, this species stands out for its vibrant green shades.
While wild species remain beautiful and sought-after, their presence in the aquarium trade has been eclipsed by the growing popularity of selectively bred strains. Over the years, breeders have developed an impressive array of discus strains, each with unique color patterns, intensity, and appeal. Some famous examples include the vibrant pigeon blood strain with its bold red markings and the shimmering turquoise discus.
It’s important to note that these strains are not separate species but are carefully bred variations of the wild discus. Selective breeding has allowed for an incredible diversity of colors and patterns, making them more accessible to aquarists. However, many hobbyists make the mistake of choosing wild discus without considering their more demanding water conditions, whereas selectively bred strains are often more adaptable.
Where do discus fish come from?
Native to the Amazon River basin in South America, these fish thrive in the slow-moving rivers, flooded forests, and shallow oxbow lakes of Brazil, Peru, and Colombia. Their natural habitat is a dynamic environment, dramatically transformed by the seasons.
During the rainy season, which begins in December, heavy tropical rains and ice-cold water from the highlands flood the Amazon River. Tributaries swell, sometimes even reversing their flow, as the river overflows into the surrounding forests. The once-clear ponds become murky as the waters mix, and the flooded forest transforms into a vast, slow-moving bog. Discus fish seek shelter among submerged roots and plants, which provide safety and a substrate for spawning.
As the rains taper off in May, the waters begin to recede, and the flooded forest gradually clears. By July, the water levels fall significantly, and isolated streams and ponds emerge. These waters become exceptionally soft and acidic, turning a dark, tea-like color due to the tannins from decomposing leaves. In these conditions, the water often becomes aseptic, with low conductivity and minimal impurities. According to discus expert H. Bleher, these fish are typically found in blackwater environments, where the riverbeds are littered with rotting leaves, and riverside plants’ roots provide year-round shelter.
When the water levels drop further, discus fish leave their hiding places and move toward deeper areas of the basin, though they avoid strong currents and large rivers. Their preference for slow-moving water and secluded habitats means that isolated populations develop unique features, particularly in their coloration, even in relatively small groups. This natural isolation has contributed to the striking variety of wild discus color patterns.
In the wild, their diet consists mainly of insect larvae and small freshwater shrimp, which they hunt among the riverbed debris. Unfortunately, a common mistake among aquarists is not providing a similar diet or water conditions. For discus to truly thrive in home aquariums, aquarists should mimic their natural environment by keeping the water soft and slightly acidic, adding leaf litter or driftwood to replicate their blackwater habitat, and offering a diet rich in protein, similar to their wild feeding habits.
Description
This is one of the cichlids which has the most flattened body and it reminds a disc, which gave the discus fish its name. Right now it’s impossible to describe coloring, since there are lots of species with different coloring which were bred by the amateur aquarists. It’ll take quite a while just to try to name the types of the coloring.
However, in the process if selection this fish has not only got a bright coloring, but also rather weak immunity and liability to diseases. Unlike the wildlife species, selected species are more demanding and picky.
Even though this species has coloring that differs quite a lot from the wildlife species, it is less adapted to life in a tank, it prones to get ill more often and requires much more care. Moreover, discus is one of the most demanding tank fish, which requires stable water parameters, a spacious tank, quality feed and the fish itself isn’t a cheap one.
How big does a discus fish get?
While discus typically grow to an average of 6 to 8 inches (15 to 20 centimeters) in diameter, several factors can influence their ultimate size, including genetics, diet, and overall care.
Genetics play a key role, as some strains are naturally larger or smaller than others. However, diet is equally important. A high-protein diet that mimics their natural intake of insect larvae and shrimp can promote faster growth, while a poor or inadequate diet may slow it down. Additionally, the size of the tank matters. Discus kept in cramped or overcrowded conditions may not reach their full potential, as stress and limited space can stunt their growth.
Aquarists aiming to help their discus grow to their full size should carefully monitor these factors. Providing a spacious tank with clean water, offering a well-rounded diet, and maintaining a stress-free environment will ensure that discus can reach their maximum size. On the other hand, common mistakes such as underfeeding or keeping discus in tanks that are too small can lead to stunted growth, leaving the fish smaller than they should be.
How fast do discus grow?
While discus typically reach full size within 1 to 2 years, growth rates can differ even within the same group of fish. Some strains of discus have unique growth patterns due to genetics, with some growing faster or larger than others. For example, high-protein foods like bloodworms or brine shrimp can encourage faster growth in young discus, while poor water quality can slow their development. It’s important for aquarists to monitor their fish’s growth and adjust their care routine accordingly.
How long do discus live?
On average, discus fish live 8 to 10 years in captivity, but some have been known to reach 12 years or more with the right conditions. While they are among the most beautiful freshwater fish, discus are also more prone to health issues and sensitive to water parameter changes compared to other species.
| Characteristic | Description |
|---|---|
| Scientific Name | Symphysodon spp. |
| Origin | Amazon River basin in South America |
| Family | Cichlidae |
| Average Size | 6-8 inches (15-20 centimeters) |
| Lifespan | 8-10 years (can live longer with proper care) |
| Body Shape | Deep-bodied and laterally compressed |
| Color Varieties | Various color variations including blues, reds, and greens |
| Temperament | Generally peaceful but can be territorial during breeding |
| Water Temperature | 82-86°F (28-30°C) |
| pH Range | 6.0-7.0 |
| Water Hardness | Soft to slightly hard water (4-12 dGH) |
| Tank Size | Minimum of 50 gallons for a pair, larger for a community |
| Diet | Primarily carnivorous, requires high-protein diet |
| Tank Decoration | Plants, driftwood, and rocks to create hiding places |
| Water Filtration | Efficient filtration with regular water changes |
| Breeding Behavior | Caring for eggs and young fry, parents are dedicated |
| Common Health Issues | Stress-related diseases, discus-specific infections |
| Special Considerations | Require clean water and stable conditions for optimal health |
Are discus fish easy to keep?
No! Discus fish is definitely for experienced aquarists, it’s decidedly not the fish for the beginners. The discus fish is very demanding, so even for an expert aquarist it can be quite challenging to keep it, especially to make it breed.
The first difficulty owner faces is the discus fish acclimatization in a new tank. Adults takes its relocation more easily, yet even they are prone to get stressed.
Large sizes, ill health, demanding to care and feed, high tank water temperature – all these issues you have to consider before buying your first discus. You’ll need a spacious tank, a very good filter, branded food and huge amount of patience.
You have to be cautious when buying the discus fish, since it tends to get ill with white spot disease and others, and relocation will cause stress and stimulate the disease development.
Diet
While these fish are known for their beauty and grace, their dietary needs can be quite specific. A high-quality, protein-rich pellet or flake food specifically formulated for discus is a great foundation. Look for products containing ingredients such as fish meal, shrimp meal, and spirulina, which provide the essential nutrients your discus needs.
Feeding Tips:
- Small, frequent meals: Since discus fish have small stomachs, it’s best to feed them small portions multiple times a day to prevent overfeeding and to accommodate their digestion.
- Variety is key: Alongside pellets or flakes, discus thrive on a mix of frozen or live foods. Examples include tubifex, bloodworms, brine shrimp, corethra, and gammarus. These foods mimic their natural diet and provide essential nutrients.
- For more experienced aquarists, discus can also be fed homemade meat mixtures. Professional aquarists often create customized recipes, which might include ingredients like ox heart, prawns, mussels, and vitamins. Some even add vegetables and nettle for extra nutritional value. However, if you’re just starting out, sticking to high-quality commercial food and occasional frozen options is a great approach.
It’s important to remember that discus are naturally timid and can be slow to approach food, especially in community tanks. For this reason, they’re often kept separately from more aggressive eaters. A common mistake aquarists make is not accounting for this, which can lead to discus fish missing meals and becoming malnourished.
Another key point to consider is the potential buildup of waste from uneaten protein-rich food, which can lead to an increase in ammonia and nitrates. This can be harmful to your discus. To avoid this, you should regularly siphon the tank bottom or opt for a bare-bottom setup, which makes cleaning easier.
Be cautious with live foods, especially bloodworms and tubifex, as they may carry diseases or cause foodborne intoxication. This is why many experienced aquarists prefer to feed their discus a mix of minced meat and artificial feeds, which are generally safer and more controlled.
By following these guidelines, you can ensure your discus get the proper nutrition they need to thrive and stay healthy in your aquarium.
Discus fish care
Tank size
These fish are sensitive to their environment, and having the right tank size is essential for their well-being. Whether you’re keeping a pair, a community, or a school of discus, here’s what you need to know about choosing the correct tank size.
For a Pair of Discus
If you plan to keep just a pair of adult discus fish, a minimum tank size of 50 gallons (190 liters) is recommended. This size allows for plenty of swimming space and provides a suitable environment for a breeding pair. Smaller tanks can stress discus, making them more prone to health issues.
Community Tank
Want to keep discus with other compatible species? A larger tank is required. For a community tank, it’s best to have at least 75 gallons (285 liters) or more. This gives enough room for multiple discus and other tank mates, reducing the chances of territorial disputes and promoting peaceful cohabitation.
Schooling Discus
Discus fish are naturally social and thrive when kept in groups. If you’re aiming for a school of discus, a tank size of at least 100 gallons (380 liters) or larger is highly recommended. The extra space allows each fish to establish its own area while reducing aggression and stress. Adding plants, driftwood, or other décor will create hiding spots and mimic their natural environment, which helps them feel more secure.
Keep in mind: A common mistake aquarists make is underestimating the tank size needed for young discus, thinking they’ll upgrade later. It’s always better to start with a larger tank to ensure they have room to grow and minimize stress. Larger tanks also provide more stable water conditions, which is crucial for discus, as they are highly sensitive to fluctuations in water quality.
Water parameters
Water quality isn’t just important for discus fish—it’s essential for their survival. These fish are highly sensitive to fluctuations in water parameters, and maintaining optimal conditions is crucial for their health. Here are the recommended water parameters for keeping discus fish happy and thriving:
Temperature
Discus fish require higher temperatures than most tropical fish. The ideal range is 82°F to 86°F (28°C to 30°C). Their preference for warmer water makes it challenging to find compatible tank mates, as many tropical species cannot tolerate such high temperatures.
pH Range
Discus fish thrive in slightly acidic to neutral water. The recommended pH level is between 6.0 and 7.0. Maintaining this range is vital to keep them comfortable and stress-free.
Water Hardness
These fish prefer soft to slightly hard water. Aim for a water hardness level of 4 to 12 degrees of General Hardness (dGH). Using a water softener or mixing tap water with reverse osmosis water can help achieve this balance.
Ammonia and Nitrate Sensitivity
Discus fish are extremely sensitive to ammonia and nitrates. Even small amounts of these substances can harm them, making regular tank maintenance crucial. Although discus don’t produce much waste, their diet—often consisting of finely minced food—can quickly break down and pollute the tank.
Maintaining Water Quality
To ensure the best environment for your discus:
- Perform weekly water changes of around 20% to 30% to remove toxins and maintain clean water.
- Use a powerful external filter to provide both mechanical and biological filtration. This helps keep the water free of uneaten food and waste.
- Regularly siphon the tank bottom to prevent the buildup of food particles and debris, especially in tanks with substrate.
- Test the water regularly for pH, hardness, ammonia, and nitrates to ensure stable conditions.
With consistent care and attention, you can create a healthy, thriving environment for your discus fish.
Tank decor
Creating a peaceful and supportive habitat is essential for the health and happiness of your discus fish. Here are some important considerations for setting up their tank:
Environmental Sensitivity
Discus fish are very timid and dislike loud sounds, sudden movements, or disturbances like knocking on the tank glass. It’s best to place the tank in a quiet location where they won’t be easily startled.
Plant Selection
Planted tanks can provide a comfortable environment for discus fish, as long as there is enough space for them to swim. However, not all plants can tolerate water temperatures above 28 °C, so careful selection is necessary. Here are some suitable options:
- Didiplis diandra
- Vallisneria
- Anubias barteri var. nana
- Giant ambulia
- Rotala indica
While discus fish can thrive in planted tanks, many aquarists choose to keep them in tanks without plants or substrate. This approach simplifies maintenance and reduces the risk of illness.
Introducing New Fish
When you first introduce discus fish to their new tank, it’s important to give them time to acclimate. Follow these steps:
- Turn off the tank lights to minimize stress.
- Avoid standing close to the tank or making sudden movements.
- Provide hiding spots using plants or decorations, giving the fish a sense of security.
By creating a tranquil environment and allowing your discus fish time to adjust, you’ll help ensure they thrive in their new home.
Temperament
Understanding their temperament and social behavior is key to creating a harmonious aquarium.
Discus fish are generally known for their peaceful nature and can coexist well with calm and compatible tank mates. Ideal companions include tetras, rasboras, and peaceful corydoras. However, during breeding or when establishing a hierarchy, discus fish may exhibit territorial behavior. This can manifest as defending a specific area of the tank and becoming more assertive towards other fish.
To minimize territorial disputes, it’s important to provide ample space and plenty of hiding spots. Decor such as driftwood, plants, and rocks can create secure areas for all fish, reducing stress and promoting a more peaceful environment.
Tank mates
Unlike other cichlid species discus is a peaceful and good tempered one. It’s not a predator and it doesn’t dig tank substrate like other cichlids. Discus is a schooling discus fish so it prefers to stay in groups of 6 species at least and it hardly stands being alone.
The difficulty when choosing tank mates for discus is that the fish is slow, it eats slow and inhabits in water with rather high for other species temperature. Due to this and also to prevent the possibility of the infection, fish is often kept in a separate tank.
But, if you still want to put some tank mates into the tank, you should consider the following:
- Many species of tetras, such as cardinal tetras, neon tetras, and rummy nose tetras, make good companions for discus fish. They are small, peaceful, and thrive in similar water conditions.
- Various species of Corydoras catfish, such as adolfoi corydoras or panda corydoras, are compatible with discus fish. They are bottom-dwelling, peaceful, and help keep the tank clean.
- Dwarf Cichlids: Some species of dwarf cichlids, such as German blue ram, can coexist with discus fish. However, it’s important to monitor their behavior as some dwarf cichlids can become territorial during breeding.
- Certain species of plecos, such as bristlenose plecos (Ancistrus sp.), can be suitable tank mates. Plecos are generally peaceful, and they help control algae growth in the tank.
- While angelfish (Pterophyllum scalare) are larger cichlids, they can be compatible with discus fish if they are introduced as juveniles and if there is enough space in the tank. Monitoring their behavior and providing suitable hiding spots is essential.
Gender differences: male vs female
Distinguishing male and female discus can be challenging, but there are a few general traits to consider:
- Head Shape: Some experienced aquarists note that males often have a more receding forehead and fuller lips than females.
- Size and Shape: Adult male discus tend to be slightly larger and exhibit a more elongated, muscular body shape compared to females.
- Coloration: In certain strains or varieties, males may display more intense and vibrant colors, especially during breeding.
- Behavior: During breeding, males are typically more active, assertive, and territorial. They engage in courtship displays, establish territories, and may show more aggressive behaviors.
Breeding
If you aim to make your discus breed, so the more species are in a school, the better. You should buy at least 6-8 young species and hope that in time you’ll get at least one couple among them.
There’s no need to interfere into the process of the couple formation – the discus fish will do it themselves.
However, it is desirable to prepare a proper sized tank for them in advance, since yesterday’s juveniles will turn into large fish quite fast. Prepare a separate spawning tank in advance as well.
What should I do if couple eats its eggs? This is quite common phenomena when discus breeding and it is often observed among the young discus fish. Don’t hurry to break up the couple. It’s better to give it a chance to grow older.
You have to let them show themselves as “parents”, usually after several unsuccessful spawning everything gets fine. You may also use a glass wall or some net to separate from the others the parent, who usually eats the eggs.
Or you can cover the spawn with some synthetic net, through which the juveniles will be able to go out later.
However, in this case the discus fish parents may completely lose their interest to the eggs. If nothing of these helps, then you should break up the couple after their 10-15 tries to spawn.
Should I continue tank water renews when the discus fish has already spawned?
For successful discus fish breeding water in the spawning tank should be very clean. If there is a possibility, stick to the routine schedule of water renews. Especially if the spawning tank is small sized (about 100 liters or 26,42 gallons).
We can recommend you to continue water renews but in smaller amounts and more often. Surely, the spawning tank water parameters must be the same as the initial tank water has. In fact, this condition is rather difficult to fulfill. That’s why lots of professional breeders prefer to stop water renews in the spawning tank for some time.
Light in the spawning tank should be dim, but it should be on 24 hours a day during spawning. Any low powered lamp placed at some distance from the spawning tank will do for this purpose.
We’d also like to remind you not to disturb the fish in the spawning tank by any other unnecessary actions inside it.
Water in the spawning tank has to be maximally soft (2-3 degrees) and slightly acidic (pH in the range of 6-6,2). In more hard and alkaline water the percentage of fertilized eggs significantly reduces.
When pH value changes to more acidic one (close to 5.5), increase of the fish phys secretion was noticed. However, a list of other issues arises then.
Also there are known the cases of some species breeding in common tap water.
Actually, we still don’t know for sure what causes unsuccessful spawning of discus. Sometimes in water which is proper for the discus fish spawning the results are rather doubtfully successful and vice versa, – in quite old water with large amount of organic wastes in it, with definitely not proper parameters one achieves 100 % juveniles yield.
Any attempt to reproduce this success usually gives zero result.
One of the criteria to make this or that decision as for the water renews is the spawning tank size, where the fish has laid its eggs. In case of large sized spawning tank you have some spare space, which can be used.
If the spawning tank is small, it’s obvious that the water will get spoiled faster and it’ll surely require renews.
So more difficult it is to perform renews in this case without changing the water parameters in the end. And the latter affects adversely the eggs and larvae.
From all these sketchy facts, that don’t cover completely all the issues as for breeding, it becomes obvious how complicated the whole process is and why it still does not happen simple and easy on an industrial scale.
Even in large Asian farms, where there are lots of tanks with discus with the same water parameters, still each couple requires custom solutions.