FastAquatics

About Discus

Symphysodon is a small genus (3 species: S. aequifasciatus, S. discus, S. tarzoo) of South American cichlid native to the Amazon basin. Wild Discus inhabit slow blackwater systems with soft, acidic water rich in tannins. Captive breeding over 60+ years has produced dozens of color and pattern strains, with prices from $80 entry-level to $500+ for premium graded specimens.

Care parameters

Tank size
75 gal+
Adult size
6-9 in
Temp (F)
82-86
pH
5.5-7.0
Hardness
Soft
Diet
Carnivore

The non-negotiables

  • Group of 5+: Discus are schooling. Single specimens get bullied; pairs form unfavorable hierarchies. 5+ disperses aggression.
  • Daily feeding (sometimes 2-3x): Beefheart blends, frozen bloodworms, brine shrimp, prepared discus pellets. Discus are heavy eaters.
  • Aggressive water changes: 25-50% twice weekly minimum. Discus excrete heavily; water quality drops fast.
  • Quiet location: sudden movements stress Discus. Place tank away from foot traffic and TVs.
  • Temperature 84F+: immune function suffers below 82F. Heat is non-negotiable.

Named strains

The captive-bred Discus economy includes:

  • Heckel Discus (S. discus) - wild form, vertical blue stripes, premium
  • Blue Diamond - solid metallic blue body
  • Marlboro Red - solid bright red
  • Pigeon Blood - white body with red pigeon markings
  • Snakeskin (Royal Blue, Red Snake) - tight pattern markings
  • Leopard / Leopard Snakeskin - heavy pattern coverage
  • Solid Blue / Cobalt / Turquoise - single-color strains
  • Pink Diamond, White Butterfly, Snow White - pale strains
  • Wild Heckel, Wild Brown, Wild Tefe Green, Wild Royal Blue, Wild Alenquer - wild-collected variants commanding premium pricing

The Discus disease problem

Discus are disease-prone. Common ailments:

  • Hexamita (Hole in the Head): internal parasite. Treat with metronidazole.
  • Gill flukes: Praziquantel treatment.
  • Discus plague: stress-triggered systemic infection. Quarantine, antibiotics, water quality.
  • Internal parasites (general): deworm prophylactically when adding new stock.

Discus require strict quarantine for any new addition. A new Discus added to an established colony without QT is the most common cause of full-tank disease outbreaks.

Compatibility

Best tankmates: cardinal tetras, rummy nose tetras, sterbai corydoras, large Apistogramma, German Blue Rams (parameter-matched). Avoid: angelfish (different size aggression), most barbs (fin nipping), any cool-water species (Discus needs heat).

Pricing tiers

  • Asian-bred entry strains (3"): $40-80 per fish
  • Mid-grade strains (4"): $100-200 per fish
  • Premium strains (5"): $200-500 per fish
  • Wild-caught varieties: $200-1,000 per fish (rare strains)
  • Show-grade specimens: $500-2,000+ per fish
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Aquarium-keeping fundamentals

Whatever specific topic brought you here, four fundamentals govern long-term aquarium success: water quality, parameter stability, biological filtration, and species-appropriate husbandry. Skip any one and the others struggle to compensate.

Water quality: ammonia + nitrite at zero, nitrate under 30 ppm freshwater + 10 ppm reef. Test weekly with API or Salifert kits. Use our water parameter checker to score your readings against your tank type.

Parameter stability: stable wrong parameters beat fluctuating ideal parameters. Most fish tolerate a wide pH range if it's stable. Sudden swings of 0.4+ pH or 5+°F kill fish faster than chronic suboptimal values. Use temperature controllers (Inkbird) + automated dosing for consistency.

Biological filtration: the bacterial colony on your filter media + rock + substrate is the engine. Never replace all media at once. Use our filter turnover calculator to size correctly.

Species-appropriate husbandry: research adult size, territoriality, diet, and tankmate compatibility before purchase. Use our tank stocking calculator + compatibility guides.

Frequently asked questions

How long does an aquarium take to set up? 4-6 weeks for full cycling + first stocking. Use our cycle ETA calculator + how long does cycling take.

What's the best aquarium for beginners? 20-gallon long. Big enough for parameter stability, small enough for budget + space. See beginner picks.

How often should I do water changes? 25-30% weekly. See water change frequency Q&A + water change calculator.

Why does my fish keep dying? 5 leading causes: uncycled tank, wrong species pairings, no quarantine, undersized tank, neglected water-change schedule. See full diagnosis.

Related resources

Saltwater livestock · Freshwater livestock · Coral catalog · Care library · Q&A library (222) · Glossary (127) · Disease database (50) · Calculators (29) · Interactive tools (7) · Husbandry deep-dives · DIY projects · State legality directory