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Compatibility Report

Can Common Goldfish Live With Red Eye Tetra?

GuideMyTank compatibility analysis for Common Goldfish and Red Eye Tetra.

Planning verdict

caution

Conditional

Only plan this pair if every listed condition can be met, and have a separation plan if stress or aggression appears.

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

Blocking risks

No automatic safety blocker was found.

Conditions and cautions

  • One species should be maintained in a proper school or group.
  • One species requires a significantly larger aquarium.
  • Specialist tank style requirements need careful matching.

Supporting factors

  • Temperature ranges overlap well.
  • pH requirements overlap well.
  • Species have similar temperament.
  • No predation risk detected.
Common Goldfish profileRed Eye Tetra profileMethodology and limitations

Why This Pair Received Its Verdict

Common Goldfish and Red Eye Tetra receive a conditional verdict from the current structured assessment. Common Goldfish is recorded as peaceful with an aggression level of 1/10; Red Eye Tetra is recorded as peaceful with an aggression level of 2/10. 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.
  • One species should be maintained in a proper school or group.

Helpful Links

Use the Compatibility CheckerRead the Compatibility Disclaimer

Water Parameter Overlap

Common Goldfish has a recorded temperature range of 60–75°F and pH range of 7–8.4. Red Eye Tetra is recorded at 72–82°F and pH 6–8. Their shared planning window is 72–75°F for temperature and 7–8 for pH. A shared aquarium must stay inside the overlap rather than merely touching each species’ outer tolerance.

Aquarium Space and Adult Size

Common Goldfish sets the larger listed base aquarium requirement at 75 gallons; the other listed minimum is 20 gallons. Common Goldfish is the larger adult by the recorded maximum, reaching 12 inches, compared with 2.8 inches. These figures are starting constraints, not a stocking-capacity calculation, because the complete group sizes and bioload still matter.

Behavior and Social Requirements

Common Goldfish is a moderate species associated with the mid zone and moderate flow. Red Eye Tetra is active, uses the mid zone, and has a moderate flow preference. Common Goldfish does not have a recorded minimum school larger than one, while red eye tetra should be planned as a group of at least 6. The aquarium must support both social structures without forcing either species into insufficient space.

Husbandry Fit

Common Goldfish is recorded as a omnivore with easy care, while Red Eye Tetra is a omnivore with easy care. Their listed preferred tank styles are goldfish and planted. 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 Common Goldfish and Red Eye 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 72–75°F.
  • Keep pH within 7–8.
  • Use at least the larger 75-gallon base requirement before accounting for the complete stocking plan.
  • Common Goldfish does not have a recorded minimum school larger than one; red eye tetra should be planned as a group of at least 6.
  • Provide a separation plan and monitor feeding, stress, chasing, damaged fins, and access to preferred habitat zones.

Final Recommendation

Only plan this pair if every listed condition can be met, and have a separation plan if stress or aggression appears.

Sources and Data Provenance

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

  • ornamentalfish.orgcare · medium confidence
  • fishbase.secare · medium confidence
  • thesprucepets.comcare · 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
Jul 2, 2026
Review status
Structured automated assessment

Related Resources

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