Compatibility Report

Can Cardinal Tetra Live With Convict Cichlid?

GuideMyTank compatibility analysis for Cardinal Tetra and Convict Cichlid.

Planning verdict

incompatible

Not recommended

Do not plan a shared aquarium for this pair. Choose a different tank mate or maintain separate aquariums.

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

Blocking risks

Size and diet create a predation risk.

Conditions and cautions

Aggressive temperament makes this pairing risky.
Tank size requirements differ slightly.
GH or KH ranges do not overlap well.
A species needing stable water has only a narrow pH, GH, or KH overlap.
Territorial footprint and swimming zone overlap require extra space and cover.
Breeding aggression can turn an otherwise workable pairing into a caution setup.

Supporting factors

Temperature ranges overlap well.
pH requirements overlap well.
Both species have compatible schooling or group behavior.

Cardinal Tetra profile Convict Cichlid profile Methodology and limitations

Why This Pair Received Its Verdict

Cardinal Tetra and Convict Cichlid receive a not recommended verdict from the current structured assessment. Cardinal Tetra is recorded as peaceful with an aggression level of 1/10; Convict Cichlid is recorded as aggressive with an aggression level of 8/10. 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.
Aggressive temperament makes this pairing risky.
Both species have compatible schooling or group behavior.

Water Parameter Overlap

Cardinal Tetra has a recorded temperature range of 73–84°F and pH range of 5–7. Convict Cichlid is recorded at 75–82°F and pH 6.6–7.8. Their shared planning window is 75–82°F for temperature and 6.6–7 for pH. A shared aquarium must stay inside the overlap rather than merely touching each species’ outer tolerance.

Aquarium Space and Adult Size

Convict Cichlid sets the larger listed base aquarium requirement at 30 gallons; the other listed minimum is 20 gallons. Convict Cichlid is the larger adult by the recorded maximum, reaching 6 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

Cardinal Tetra is a calm species associated with the mid zone and moderate flow. Convict Cichlid is moderate, uses the cave zone, and has a moderate flow preference. Cardinal Tetra should be planned as a group of at least 8, while convict cichlid should be planned as a group of at least 2. The aquarium must support both social structures without forcing either species into insufficient space.

Husbandry Fit

Cardinal Tetra is recorded as a omnivore with intermediate care, while Convict Cichlid is a omnivore with intermediate care. Their listed preferred tank styles are blackwater and rockwork. 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 Cardinal Tetra and Convict Cichlid; 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.
A different tank mate is the preferred decision for this pair. Attempting the combination transfers the identified risk to the animals rather than resolving it.

Aquarium Planning Checklist

Keep temperature within 75–82°F.
Keep pH within 6.6–7.
Use at least the larger 30-gallon base requirement before accounting for the complete stocking plan.
Cardinal Tetra should be planned as a group of at least 8; convict cichlid should be planned as a group of at least 2.
Choose separate aquariums or a different tank mate instead of attempting to manage a known blocking risk.

Final Recommendation

Do not plan a shared aquarium for this pair. Choose a different tank mate or maintain separate aquariums.

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
thesprucepets.comcare · 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

Continue with the most relevant care and compatibility resources for Cardinal Tetra and Convict Cichlid.