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Compatibility Report

Can Brilliant Rummynose Tetra Live With Cardinal Tetra?

GuideMyTank compatibility analysis for Brilliant Rummynose Tetra and Cardinal Tetra.

Planning verdict

compatible

Recommended

This pair is a reasonable starting point when both species receive their required tank size, group size, water conditions, and routine care.

Data confidence
high
Assessment source
Structured data model
Data completeness
100%

Blocking risks

No automatic safety blocker was found.

Conditions and cautions

No additional conditional requirements were identified.

Supporting factors

  • Temperature ranges overlap well.
  • pH requirements overlap well.
  • Species have similar temperament.
  • Both species have compatible schooling or group behavior.
  • No predation risk detected.
  • Tank size requirements align.
Brilliant Rummynose Tetra profileCardinal Tetra profileMethodology and limitations

Why This Pair Received Its Verdict

Brilliant Rummynose Tetra and Cardinal Tetra receive a recommended verdict from the current structured assessment. Brilliant Rummynose Tetra is recorded as peaceful with an aggression level of 1/10; Cardinal Tetra is recorded as peaceful with an aggression level of 1/10. The recommendation is based on the combined water, space, behavior, grouping, and predation checks below rather than on species names alone.

  • Temperature ranges overlap well.
  • pH requirements overlap well.
  • Species have similar temperament.
  • Both species have compatible schooling or group behavior.

Helpful Links

Use the Compatibility CheckerRead the Compatibility Disclaimer

Water Parameter Overlap

Brilliant Rummynose Tetra has a recorded temperature range of 75–82°F and pH range of 5.5–7. Cardinal Tetra is recorded at 73–84°F and pH 5–7. Their shared planning window is 75–82°F for temperature and 5.5–7 for pH. A shared aquarium must stay inside the overlap rather than merely touching each species’ outer tolerance.

Aquarium Space and Adult Size

Brilliant Rummynose Tetra sets the larger listed base aquarium requirement at 20 gallons; the other listed minimum is 20 gallons. Brilliant Rummynose Tetra is the larger adult by the recorded maximum, reaching 2 inches, compared with 2 inches. These figures are starting constraints, not a stocking-capacity calculation, because the complete group sizes and bioload still matter.

Behavior and Social Requirements

Brilliant Rummynose Tetra is a moderate species associated with the mid zone and moderate flow. Cardinal Tetra is calm, uses the mid zone, and has a moderate flow preference. Brilliant Rummynose Tetra should be planned as a group of at least 8, while cardinal tetra should be planned as a group of at least 8. The aquarium must support both social structures without forcing either species into insufficient space.

Husbandry Fit

Brilliant Rummynose Tetra is recorded as a omnivore with intermediate care, while Cardinal Tetra is a omnivore with intermediate care. Their listed preferred tank styles are blackwater and blackwater. Feeding access, cover, open swimming room, filtration, and observation should be planned around the more demanding requirement rather than averaged between the two species.

What Would Change the Decision?

Use these pair-specific boundaries before treating the verdict as an acceptable stocking plan.

  • Do not proceed unless one stable temperature and pH range can be maintained for both Brilliant Rummynose Tetra and Cardinal Tetra; acclimation does not correct an incompatible long-term range.
  • Treat size, predation, and fin-damage warnings as stop conditions. Extra plants cannot reliably make an unsafe predator-to-prey or fin-target pairing safe.
  • Use broken sight lines and multiple retreats, then separate the pair if either species shows persistent chasing, hiding, clamped fins, or loss of feeding access.
  • Recalculate space using the full adult group sizes—not one specimen of each species—and reject the plan if either species must be understocked socially to fit.
  • Prepare a cycled backup or separation option before introduction; individual behavior can be less predictable than species-level records.

Aquarium Planning Checklist

  • Keep temperature within 75–82°F.
  • Keep pH within 5.5–7.
  • Use at least the larger 20-gallon base requirement before accounting for the complete stocking plan.
  • Brilliant Rummynose Tetra should be planned as a group of at least 8; cardinal tetra should be planned as a group of at least 8.
  • Provide a separation plan and monitor feeding, stress, chasing, damaged fins, and access to preferred habitat zones.

Final Recommendation

This pair is a reasonable starting point when both species receive their required tank size, group size, water conditions, and routine care.

Sources and Data Provenance

These references support the underlying species records used by this assessment. They do not necessarily evaluate this exact pair together.

  • fishbase.secare · medium confidence
  • fishbase.secare · medium confidence
  • thesprucepets.comcare · medium confidence
  • en.wikipedia.orgtaxonomy · medium confidence
  • en.wikipedia.orgtaxonomy · medium confidence
  • en.wikipedia.orgtaxonomy · medium confidence
  • en.wikipedia.orgtaxonomy · medium confidence
Read the full methodology and limitations
Report quality
supported
Analysis version
2026.09.1
Species data updated
Sep 29, 2026
Review status
Structured automated assessment

Related Resources

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