Discus fish (genus Symphysodon), frequently crowned the "King of the Aquarium," are highly prized freshwater cichlids native to the lowland Amazon River basin. Famous for their compressed, disc-like bodies, intense colors, and graceful movements, they have generated a dedicated global following. While stunning, they have strict care requirements, making them better suited for intermediate to advanced aquarists rather than beginners. 
Care Quick-Stats
Parameter    Ideal Target
Tank Size    Minimum 55–75 gallons for a school
Temperature    Very warm: 82°F to 88°F (28°C–31°C)
Water pH    Soft and acidic: 6.0 to 6.8 (Stability is key)
 
 

Diet    Omnivorous: Pellets, flakes, bloodworms, and beef heart
Lifespan    10 to 15 years with proper maintenance
Key Care & Behavior Instincts
Social Structure: Discus are highly social schooling fish and must be kept in groups of 5 or more. Keeping them in pairs or small groups often leads to severe bullying and stress, which can cause them to turn dark and get sick.  
Water Quality: They are exceptionally sensitive to pollutants. Pristine water condition is mandatory, typically requiring robust canister filtration alongside 25% to 50% weekly water changes to keep nitrates near zero. 
Feeding Dynamics: They are notoriously slow, deliberate grazers. If they are housed with fast-swimming tank mates (like larger tetras or barbs), the discus will easily be outcompeted for food and suffer from malnutrition. 
Unique Parenting: Discus are among the few fish that explicitly nurse their young. Both parents secrete a nutritious slime coat from their skin, which the newly hatched fry graze on for the first few weeks of life.