TankStocking

Can Discus live with Cardinal Tetra?

Yes — Discus and Cardinal Tetra are a workable pairing in a suitable, cycled tank.

By the TankStocking team · methodology-driven, sourced from aquarium care references Data v2026.06 · last reviewed How we judge this →

The planner's verdict

Discus + Cardinal Tetra

✓ Good starter plan

5× Discus, 6× Cardinal Tetra

The engine clears this pairing — a workable starting point in a cycled, planted tank.

Load this build in the planner ↑

Discus vs Cardinal Tetra: key facts

A neutral, side-by-side look at each species' sourced stats. These are figures only — the verdict above states whether they should share a tank.

Key facts side by side — Discus vs Cardinal Tetra (sourced stats only)
Key factDiscusCardinal Tetra
Adult size20 cm3 cm
Minimum tank55 US gal15 US gal
Minimum group5+ (shoal)6+ (shoal)
TemperamentPeacefulPeaceful
Temperature range28–30°C23–29°C
pH range6–7.54–7.5
BioloadHighLow
Swim levelMidwaterMidwater
Beginner-friendlyNo — advancedYes

Why, at a glance

Drawn straight from the sourced figures above, using the same thresholds the engine applies — these show the data behind the verdict, not a separate opinion.

Temperature range overlap — Discus vs Cardinal Tetra Shared temperature window: 28–29°C (1°C overlap). Both ranges include it. Discus: 28–30°C Cardinal Tetra: 23–29°C shared 14°C32°C
Temperature range overlap. Shared temperature window: 28–29°C (1°C overlap). Both ranges include it.
pH range overlap — Discus vs Cardinal Tetra Shared pH range: 6–7.5. Both prefer water within it. Discus: 6–7.5 Cardinal Tetra: 4–7.5 shared 48.5
pH range overlap. Shared pH range: 6–7.5. Both prefer water within it.
Adult size to scale — Discus vs Cardinal Tetra Discus (20 cm) is 6.7× the length of Cardinal Tetra (3 cm) — under the 3.5× size gap that flags predation risk. Discus: 20 cm Cardinal Tetra: 3 cm 10.5 cm = 3.5× line 0 cm
Adult size to scale. Discus (20 cm) is 6.7× the length of Cardinal Tetra (3 cm) — under the 3.5× size gap that flags predation risk.
Sources & confidence (2 species)

These back the Discus and Cardinal Tetra figures used for this verdict. Each figure is read from the TankStocking species database (v2026.06); below is the care reference behind it and how confident we are in that data. Confidence reflects the source quality, not whether any pairing is safe. Full source list and the welfare model are on the methodology page.

  • Discus Symphysodon aequifasciatus — Aquarium Co-Op (aquariumcoop.com/blogs/aquarium/discus-care-guide); FishLore high confidence
  • Cardinal Tetra Paracheirodon axelrodi — Seriously Fish (seriouslyfish.com/species/paracheirodon-axelrodi) high confidence

Why

No welfare check fires for this pairing: their adult sizes, temperaments, temperature ranges and social needs line up. Keep each in its proper group and give the tank time to mature.

A workable setup: at least 55 US gallons (208 L), with a group of 5+ Discus and a group of 6+ Cardinal Tetra, in a cycled, planted tank. Test your exact plan below.

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      Verdict

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      Other species the engine clears with Discus — tap to load the pairing.

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      Common questions

      Can Discus live with Cardinal Tetra?

      Yes — Discus and Cardinal Tetra are a workable pairing in a suitable, cycled tank. TankStocking's engine reaches this by checking minimum tank size, group needs, temperature overlap, aggression, predation by size and fin-nipping for this exact pairing.

      What tank size do Discus and Cardinal Tetra need together?

      Plan for at least 55 US gallons so both species clear their minimum-tank needs, with a group of 5+ Discus and a group of 6+ Cardinal Tetra. More water and a planted layout with broken sightlines always help.

      Related to Discus & Cardinal Tetra

      Related guides on TankStocking — each scored by the same welfare engine as the planner.

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      This is a planning estimate based on sourced species data — individual fish vary. See the methodology, the Discus tank mates guide, or the full fish list.