The Right Discus Aquarium

The Right Aquarium for Discus Fish

Discus fish are schooling animals and thrive in clean, well-maintained aquariums with an appropriate group size.

For adult discus fish (over 10 cm):

• An aquarium of 400 liters or more is ideal.
• 8–10 discus fish make a good group size.
• Rule of thumb: 40–50 liters of water per adult fish.
• The aquarium should be set up as follows: light substrate, roots for shelter, and some robust plants (e.g., background or epiphytic plants).
• The aquarium should remain uncluttered, with plenty of open swimming space, allowing the fish to move calmly and making maintenance easy.
• The group size should not be less than 6 fish, as smaller groups often lead to stress.

For young discus fish (under 10 cm):

• Aquariums of 100–200 liters are well suited.
• Plan for 10–20 liters of water per fish.
• These tanks should remain bare, without substrate or decor, so that the bottom can be easily siphoned and the water kept clean.
• Young discus should be kept in groups of 10 or more. Smaller groups are often restless. A larger group also ensures healthy feeding competition, so that all fish eat well.

Technology and Maintenance:

• Strong, reliable filtration is mandatory.
• Oxygen supply via an air pump is recommended.
• An oxydator additionally helps to keep the oxygen level stable and provides protection during power outages.
• A UVC clarifier is recommended to keep germ levels low in the aquarium and thus support the health of the fish.
• Dimmable LED lighting is ideal. The light should not be too bright, and a gentle change in lighting prevents the discus fish from being startled when the light is switched on or off.