Why Discus Are Different
Discus (Symphysodon) come from the warm, soft, slow-moving waters of the Amazon. They evolved to live in groups of 8–15 fish in tannin-stained pools.
Three things separate discus from every other cichlid: they need 84–86°F water (warmer than most tanks), they require very clean water (nitrates under 10 ppm), and they refuse to thrive when kept alone or in pairs.
Tank Setup
Minimum 75-gallon for a starter group of 6 juveniles. Adults need 125-gallon for the same group.
Tall tanks suit discus better than long tanks because discus are vertically deep-bodied. A 30-inch tall tank gives them swimming room.
Sand or bare-bottom substrate. Bare-bottom is the choice for serious discus keepers because waste is easy to siphon and growth is monitored visually.
Water Parameters
Temperature: 84–86°F (29–30°C) — this is non-negotiable.
pH: 6.0–7.0 (wild discus prefer 5.5).
GH: 1–4 (very soft).
KH: 1–3.
Nitrates: under 10 ppm — daily for juveniles, weekly 50% changes for adults.
Most tap water requires RO mixing to soften enough for discus.
Diet
Discus traditionally eat beef heart paste — a homemade mix of trimmed beef heart, shrimp, vitamins, and binding agents. This produces the famous size and color but is high-maintenance.
Modern alternative: high-quality discus pellets (Tetra Discus, Hikari Discus Bio-Gold) plus frozen bloodworms, brine shrimp, and white mysis shrimp.
Feed juveniles 4–6 times daily for first 6 months. Adults 2–3 times daily.
Common Diseases
Discus are prone to: hexamita (internal parasite causing white stringy poop), hole-in-the-head (related to hexamita), gill flukes, and bacterial infections.
Treat hexamita with metronidazole. Quarantine new fish for 4–6 weeks before adding to display tank.
Color Strains
Wild Heckel, wild blue, wild green, and wild brown are the four wild types. Captive strains include Pigeon Blood, Red Turquoise, Blue Diamond, Snakeskin, and dozens more.
Show-quality fish from German, Malaysian, or Singaporean breeders sell for $80–500 per juvenile. Pet store discus sell for $30–80.