Compatibility Report

Can Clown Killifish Live With Wrestling Halfbeak?

GuideMyTank compatibility analysis for Clown Killifish and Wrestling Halfbeak.

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 may be semi-aggressive and require planning.
Tank size requirements differ slightly.
Water hardness preferences conflict.
GH or KH ranges do not overlap well.
A species needing stable water has only a narrow pH, GH, or KH overlap.

Supporting factors

Temperature ranges overlap well.
pH requirements overlap well.
Both species have compatible schooling or group behavior.
No predation risk detected.

Clown Killifish profile Wrestling Halfbeak profile Methodology and limitations

Why This Pair Received Its Verdict

Clown Killifish and Wrestling Halfbeak receive a conditional verdict from the current structured assessment. Clown Killifish is recorded as peaceful with an aggression level of 1/10; Wrestling Halfbeak is recorded as semi-aggressive with an aggression level of 4/10. 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.
One species may be semi-aggressive and require planning.
Both species have compatible schooling or group behavior.

Water Parameter Overlap

Clown Killifish has a recorded temperature range of 68–79°F and pH range of 5–7. Wrestling Halfbeak is recorded at 75–82°F and pH 6.5–8. Their shared planning window is 75–79°F for temperature and 6.5–7 for pH. A shared aquarium must stay inside the overlap rather than merely touching each species’ outer tolerance.

Aquarium Space and Adult Size

Wrestling Halfbeak sets the larger listed base aquarium requirement at 20 gallons; the other listed minimum is 5 gallons. Wrestling Halfbeak is the larger adult by the recorded maximum, reaching 3 inches, compared with 1.4 inches. These figures are starting constraints, not a stocking-capacity calculation, because the complete group sizes and bioload still matter.

Behavior and Social Requirements

Clown Killifish is a calm species associated with the top zone and moderate flow. Wrestling Halfbeak is calm, uses the top zone, and has a moderate flow preference. Clown Killifish should be planned as a group of at least 6, while wrestling halfbeak should be planned as a group of at least 4. The aquarium must support both social structures without forcing either species into insufficient space.

Husbandry Fit

Clown Killifish is recorded as a carnivore with intermediate care, while Wrestling Halfbeak is a carnivore with advanced care. Their listed preferred tank styles are blackwater 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 Clown Killifish and Wrestling Halfbeak; 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 75–79°F.
Keep pH within 6.5–7.
Use at least the larger 20-gallon base requirement before accounting for the complete stocking plan.
Clown Killifish should be planned as a group of at least 6; wrestling halfbeak should be planned as a group of at least 4.
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.

my-fish.orgcare · medium confidence
fishbase.secare · medium confidence
fishbase.secare · 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: Jul 2, 2026
Review status: Structured automated assessment

Related Resources

Continue with the most relevant care and compatibility resources for Clown Killifish and Wrestling Halfbeak.