Discus breeding tank: complete setup and a €600–1000 budget

In short

• Tank: 180L (48 US gal) bare-bottom, 90×45×45 cm (35×18×18 in) — recommended. Minimum 120L (32 US gal) (80×40×40 cm / 31×16×16 in).
• Substrate: NONE — a painted black/brown bottom for security.
• Spawning surface: a 15–20 cm (6–8 in) ceramic cone (€8–20) or an Anubias leaf.
• Filter: a sponge filter is ESSENTIAL (air-driven) — never external (it sucks up fry).
• Heating: 2× 100W with a ±0.5°C (±1°F) thermostat (safety).
• Parameters: 30–31°C (86–88°F), pH 5.8–6.5, KH 1–3 dKH, TDS 50–150 ppm, remineralized RO water.
• Lighting: dim (30% of normal), 3000–5000K, 8–10h/day + a night light.
• Total budget: €300–500 (without the tank), €600–1000 including the tank.

What you'll learn

The discus breeding tank (Symphysodon) is the investment that makes the difference between occasional breeding with low success rates and a consistent hatchery with regular spawns. While discus can lay eggs in a community tank, a dedicated tank offers: a far higher success rate (precisely controlled parameters), protection for the eggs and fry from curious fish, reduced stress for the pair, easy monitoring, and the ability to apply precise conditioning and artificial-raising protocols. The optimal setup: a 180L (48 US gal) bare-bottom tank (90×45×45 cm / 35×18×18 in), a ceramic spawning cone, an air-driven sponge filter (not external — it sucks up fry), 2× 100W heaters with a ±0.5°C thermostat, remineralized RO water at TDS 80–120 ppm. This guide walks you through each component, the 14-day prep timeline and the total budget of €600–1000.

Why a dedicated breeding tank?

✅ A far higher success rate (controlled parameters) ✅ Protection for eggs and fry (no other curious fish) ✅ Reduced stress for the pair ✅ Easy monitoring of the process ✅ Parameter control for each phase ✅ Applying specialized protocols (conditioning, fry feeding)

Tank size

Shape: tall and narrow > wide and flat. Discus prefer to spawn on vertical surfaces — you need a minimum height of 45 cm (18 in).

A lid is essential — it reduces heat loss, prevents jumping and keeps humidity for fry near the surface.

Substrate — bare bottom is essential

Bare bottom (no substrate) is THE STANDARD for breeding.

A painted black or brown background — reduces reflection and makes the discus feel secure. Acrylic paint or a background film stuck on from outside.

The spawning site

Discus spawn on clean vertical surfaces. Tested options:

1. A ceramic cone ⭐⭐⭐⭐⭐ (the best)

• A red or brown ceramic cone, 15–20 cm (6–8 in) tall
• A rough surface — eggs adhere well
• Easy to remove after spawning (you can transfer the eggs for artificial raising)
• EU price: €8–20 (Aquasabi, Garnelio, eBay)

Positioning: in the middle or front, with free space around it for the parents.

2. A large Anubias leaf ⭐⭐⭐⭐

• Anubias barteri with 10–15 cm (4–6 in) leaves
• Tied to a rock or decor
• Natural and preferred by the pair
• Downside: the leaf wears over time

3. A vertical PVC pipe ⭐⭐⭐

• New, clean PVC tube, 8–12 cm (3–5 in) diameter, 20 cm (8 in) tall
• Clean with vinegar + hot water first
• Cheap (€1–2)

4. A flat vertical stone ⭐⭐⭐

• Slate or natural stone leaned against the wall
• A flat, clean surface

Water parameters for breeding

Stricter than for standard maintenance:

How to reach these parameters:

1. RO water + minimal remineralization — see reverse osmosis (RO) and RO water remineralization.
2. Catappa (Indian almond) leaves for natural tannins — see blackwater.
3. Stable KH 2–3 dKH — important for pH stability.

🧮 For a target TDS of 80–120 ppm, use the RO + tap water mixer calculator — get the exact recipe instantly.

Filtration — a sponge filter is ESSENTIAL

ESSENTIAL: a sponge filter, NOT an external filter!

Why a sponge?

✅ Gentle suction — can't swallow fry ✅ Excellent biological filtration ✅ Silent ✅ Easy to clean ✅ Cheap (€10–25)

Recommended models (Europe)

Runs on an air pump — no motor that risks sucking up fry.

Positioning: in the corner opposite the spawning site, with no strong current.

Aeration

The air pump feeding the sponge also provides oxygenation. 2 air pumps (one spare) recommended.

Models: Tetra APS 50 (€10), Eheim Air (€25), JBL ProSilent (€20).

Heating

2 smaller heaters instead of one large one (safety against failure):

• 2 × 100 W for a 180 L (48 US gal) tank
• A precise thermostat (±0.5°C / ±1°F)
• Recommended brands: Eheim Jäger, Aquael, JBL ProTemp

See the detailed guide on the ideal discus temperature.

Lighting

Dim and diffuse — discus prefer filtered light for breeding.

At night: a dim night light (1W LED) — helps the discus guard the eggs and fry.

A minimalist layout

Minimal decor for breeding:

• 1 floating plant (Amazon frogbit) — shade and security
• 1 spawning cone + possibly 1 adjacent stone
• NOTHING ELSE

Why minimalism:

• Easy to clean
• No contamination
• Focus on the pair and fry
• Efficient daily siphoning

Preparing the tank — a 14-day timeline

Day -14 (2 weeks before)

• Full setup: tank, sponge filter, heaters, cone
• RO water remineralized to target parameters (see remineralization)
• Start the filter

Day -10

• Add mature biological media from another filter (a sponge from another tank)
• OR add starter bacteria (Seachem Stability, JBL Denitrol)

Day -7

• Test all parameters (see how to test your water)
• Add catappa leaves (1 leaf per 50L / 13 US gal)
• Let it mature for one more week

Day -3

• A final parameter check
• A light siphon if dust has gathered

Day 0 — transferring the pair

• In the morning, after the normal feeding in the main tank
• Transfer with a large net, stress-free
• Drip-acclimate for 1 hour if the parameters differ

Feeding the pair

2 weeks before — "conditioning"

See the full protocol in Conditioning the pair, 28 days.

• Protein-rich food: beef heart, brine shrimp, bloodworms
• 3–4 meals/day
• Extra vitamins (JBL Atvitol)

In the breeding tank

• Continue the protein diet
• 3 meals/day
• Siphon out leftovers immediately (a maximum of 10 min after feeding)

Signs that breeding is near

1. The pair approaches the cone and inspects it
2. Obsessive cleaning of the spawning surface
3. Intensified colors in both partners
4. A visible genital papilla — see Sexing discus
5. Synchronized behavior — swimming together, touching

Daily maintenance during breeding

Daily

• Siphon out food leftovers (careful not to disturb the pair)
• Check the temperature
• Observe behavior

Every 2 days

• A 10–15% water change with same-parameter water
• Test critical parameters (pH, ammonia, nitrite)

DO NOT

❌ Large water changes (>25%) that shift the parameters ❌ Noise, strong disturbances ❌ Other interventions

The parental vs artificial method

See the detailed guides: the breeding process, egg care and incubation and raising fry for 12 weeks.

Common mistakes

❌ An external filter in the breeding tank → sucks up fry within 24h.

❌ Substrate (sand, gravel) → eggs get lost, hygiene impossible.

❌ Direct tap water → KH 8+ dKH, pH 7.5+ = inhibits fertilization.

❌ A single large heater (200W+) → a failure = a thermal catastrophe.

❌ Bright lights at night → the parents abandon the eggs.

❌ Large water changes during incubation → the eggs turn white.

❌ Abundant decor → hides the fry, hard to monitor.

❌ Skipping conditioning → delayed spawns or infertile eggs.

Final checklist — complete setup

• ☐ A 180L+ (48 US gal+) bare-bottom tank, dark bottom (black/brown)
• ☐ 2× 100W heaters with a precise thermostat
• ☐ A sponge filter (air-driven)
• ☐ 2 air pumps (1 spare)
• ☐ A ceramic spawning cone
• ☐ A simple LED lamp + a night light
• ☐ RO water remineralized to TDS 80–120 ppm
• ☐ Catappa leaves for tannins
• ☐ A digital thermometer
• ☐ Full tests (pH, ammonia, nitrite, KH, GH)
• ☐ A lid
• ☐ A filter cycled 14 days before transferring the pair

Total estimated budget (Europe)

Costs vary widely by country — the figures below are orientation estimates only:

What to do next

📚 Continue learning:

• Conditioning the pair, 28 days — biological prep before transfer
• Sexing discus — confirm the pair
• Selecting the breeding pair — 7 quality criteria
• The breeding process — 6 phases step by step
• Egg care — 72h incubation
• Artificial raising — an essential Plan B

🔧 Practical resources:

• RO + tap water mixer calculator — the exact TDS for breeding
• Aquarium volume calculator — confirm the dimensions
• Breeding equipment — shop — cones, sponges, heaters

🐠 Final tip: Don't economize on the sponge filter and dual heaters — they're the only components between success and catastrophe. An external filter that sucks up fry, or a failed heater dropping the temp below 28°C (82°F), can cost you a whole spawn.