As the name suggests, discus fish are shaped like round discs – but discs that come in dazzling colours. Originating from the South American Amazon region, they now brighten up aquariums everywhere. These fish are typically kept in groups of five to eight, which can increase costs.
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Discus fish belong to the cichlid family and often appear in neon-like yellow, blue and red hues
Discus fish belong to the cichlid family and their flat, circular bodies set them apart. Their scales can display a variety of shades. They often appear in neon-like yellow, blue and red hues.
Under their broad foreheads is a flat mouth, whose lips often look slightly puffed. Their fins adorn their back and belly, often providing a contrast to the rest of the body. In comparison, their tail fins are small and narrow. Unique to them are the mood bands that surface on their bodies, changing intensity with the fish’s temperament, which serve as important indicators of stress. Discus fish are typically 12 to 16cm long, although bred fish can reach up to 20cm.
Researchers discovered the first discus fish in Brazil in the 19th century, naming it the True Discus. This fish had the classic flat shape with yellowish stripes, a white base and a prominent black band. Subsequently, more species were identified, primarily distinguished by their fin and scale colouring, which varied by environment. Today, discus fish are thought to lack clear categorisation into distinct species due to variances in characteristics even within a single type.
Aquarists often recognise four wild discus fish species:
The Heckel Discus is the most challenging to keep in an aquarium as it requires very soft, warm water with a low pH. Breeders have developed many other variants, including a blue-turquoise type and a ‘Blue Diamond’ variant with shimmering effects. Popular pet options also include the yellow ‘Pigeon Blood’ and the red-turquoise variety.
Upon its initial discovery, biologists dubbed the discus fish the ‘King of the Amazon’. These fish inhabit the fresh waters of the Amazon, its delta and its tributaries like the Rio Negro and Rio Madeira, extending into Peru. Today, you can find these vibrant cichlids in nearly all Amazon tributaries.
In the wild, interbreeding among different ‘species’ or families rarely occurs, resulting in regional variations – yet they all belong to the same species. Typically, pet discus fish are bred and distributed through pet shops or online retailers. It’s always advantageous to purchase them directly from a shop after getting thorough advice.
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Initially, young discus fish feed on the skin of their parents. When the larvae are about four weeks old, they start consuming external food. In nature, they eat algae and decaying water plants, as well as small invertebrates like mosquitoes, worms and larvae.
In an aquarium, a diverse diet is crucial. Granules and flake food are staple options but should not be overfed. Overfeeding granules can cause intestinal blockages, leading to death. Flakes should be pre-soaked to avoid them swelling in the fish’s stomach. Dry food mixes of fish fillet and shrimp are ideal, supplemented with astaxanthin or beta-carotene to enhance red colouring, reduce stress, and aid breeding.
Frozen food such as mosquito larvae, shrimp, artemia and krill also works well. Discus fish are often fed beef or turkey hearts, which should be low fat and finely chopped. These hearts promote growth but not vibrant colouring. Additionally, adding crustaceans and vegetables like bell peppers can be beneficial.
Live food like worms, small crustaceans and red mosquito larvae can stimulate their hunting instincts and general well-being. It’s also advisable to mix minerals and vitamin B12 into their food. Fibre aids digestion and prevents overfeeding, with many fibres found in the shells of crustaceans. Feeding should be done three times daily with small portions, while younger fish can be fed up to five times a day.
Everything starts with purchasing a suitable aquarium. As discus fish are typically kept in groups, more space is always better. Allocate about 60 litres of water per fish. For a group of three fish, you’ll need nearly 200 litres. Generally, groups of four to five fish are kept, requiring about 300 litres, and a minimum tank length of 150cm. Larger aquariums need to be sturdier – for more than 400 litres, a glass thickness of 12mm is necessary and a solid base is essential.
Set up the aquarium in a quiet corner of your living room, where the fish won’t be disturbed frequently. Constant stress can lead to illness and even death. Light is another potential stressor. In their natural habitat, discus fish live at the dark bottoms of Amazon rivers. Wild-caught specimens require subdued lighting. Bred fish are more accustomed to bright environments, but lights with a stronger red component are recommended. Regulate the day-night cycle by turning lights off after 12 to 14 hours for night-time.
High temperatures are vital for these tropical fish, with ideal values around 29°C. Falling below 27°C can make them nervous. The water pH should be between six and seven, although wild fish can tolerate as low as five. Higher pH levels inhibit the breakdown of ammonium secretions, risking poisoning. Water hardness should be between four and 14 degrees, with carbonate hardness between three and 12 degrees.
Filters are indispensable for maintaining a clean habitat, especially with large water volumes. Activated carbon filters are relatively low-maintenance and remove toxins from the water. An overflow system oxygenates the water, using bio-balls or lava stones. Peat can be included in one of the filter compartments. Partial water changes of about 20 to 30% weekly are recommended. Alternatively, an expensive continuous fresh water supply system can be used.
Before buying discus fish, ‘cycle’ the aquarium for about two weeks to develop beneficial bacteria that help break down harmful substances. Only introduce the fish once the habitat is fully established. Including water plants is crucial, though choosing suitable specimens can be challenging as they must withstand high temperatures. Fertilisation and CO2 supply are essential too.
Discus fish thrive in smaller groups of up to eight, crucial for natural social dynamics and hierarchy, ensuring their well-being. The optimal number is five to eight, but three fish can sometimes be kept together. Other fish species can also coexist, such as labyrinth fish, barbs, catfish, loaches and African cichlids.
Discus fish are remarkably hardy, living up to ten years in nature and up to 16 years in an aquarium. Common ailments include aluminium poisoning and fungal infections, usually preventable with good water filtration. Anchor worms, which embed in fish scales, are rare. A more frequent issue is the white spot disease, caused by protozoa. Infected fish should be isolated immediately as it’s highly contagious and often fatal. The disease is identifiable by white spots and swollen gills. Internal illnesses include dropsy, tapeworms and balance disorders.
Your first stop should be the local pet shop, where staff provide comprehensive advice on fish care and can order various species upon request. As popular aquarium fish, most shops stock discus fish.
The zooplus editorial team consists of a dedicated team of experts with many years of experience in the field of animal husbandry: Luisa with her White Swiss Shepherd Elyos, Laura, Julio, and Florian. Together with a large network of animal experts, we work to make the zooplus magazine a trusted source of information for all animal owners and lovers. Our goal is to provide exciting animal knowledge and relevant information on the proper care of pets.
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