Can Flowerhorn live with Lyretail Killifish?
High risk due to water mismatch, aggression, or predation.
Why Flowerhorn and Lyretail Killifish Don't Make an Easy Pair
There is no temperature overlap — Flowerhorn needs 78-86°F while Lyretail Killifish needs 72-77°F. One of them will be outside its safe range constantly, which leads to chronic stress and disease. The size gap is 9.5" — Flowerhorn (12.0") and Lyretail Killifish (2.5"). A fish that fits in another fish's mouth will eventually end up there.
Flowerhorn
Amphilophus hybrid
| Adult Size: | 12.0" |
| Temperament: | aggressive |
| Min Tank: | 75 gal |
| Temperature: | 78-86°F |
| pH Range: | 6.5-8.0 |
Lyretail Killifish
Aphyosemion australe
| Adult Size: | 2.5" |
| Temperament: | peaceful |
| Min Tank: | 10 gal |
| Temperature: | 72-77°F |
| pH Range: | 6.0-7.0 |
Water Parameter Overlap
| Parameter | Flowerhorn | Lyretail Killifish | Overlap |
|---|---|---|---|
| Temperature | 78-86°F | 72-77°F | No overlap ✗ |
| pH | 6.5-8.0 | 6.0-7.0 | 0.5 ✓ |
Compatibility Breakdown
Temperament Match: aggressive + peaceful. One aggressive → predation/nipping risk.
⚠️ Size Predation Risk: Flowerhorn (12.0") vs Lyretail Killifish (2.5"). A 9.5" gap — the larger fish will view the smaller fish as food.
⚠️ Diet Conflict: A carnivore sharing water with a fish small enough to fit in its mouth is a waiting game. Feed generously, but the risk is structural — not something you can manage meal by meal.
Score: -5.0/100 (GOOD ≥80, CAUTION ≥50, RISKY <50).
🔧 Tank Setup Requirements (for Both)
- Minimum tank: 75 gallons — sized for the larger fish in the pair.
- Temperature: no safe overlap range exists. A heater is not enough to fix this pairing.
- pH: maintain 6.5 – 7.0.
- Hiding spots: essential for Lyretail Killifish — caves, plants, or driftwood to retreat when feeling stressed.
- Water changes: 25% weekly minimum. Two species mean double the bioload.
🔧 Tank Stocking Calculator
Enter tank size to calculate safe stocking levels:
Recommended Equipment
Based on tank size 75+ gallons:
Large pellet food for big cichlids like flowerhorn
Explore Related Checks
See what else works with these fish:
⚠️ Common Reasons This Pairing Fails in Practice
- Zero temperature overlap: No heater setting can satisfy both species. One will be chronically stressed, leading to disease susceptibility.
- Size-based predation: The 9.5" size gap means the larger fish may eat the smaller one once it grows to full size. This is not fixable with more hiding spots.
- Diet-driven aggression: A carnivore sharing a tank with bite-sized tank mates creates structural risk — no amount of generous feeding eliminates the instinct to hunt.
- Aggression risk: An aggressive species will dominate feeding zones and chase the other fish into hiding. Chronic stress weakens the immune system and shortens lifespan.
- Overcrowding: Even compatible species fail in tanks that are too small. Double the species means double the bioload — 25% weekly water changes are the minimum.
- Inadequate acclimation: Adding both species on the same day without quarantine is a common mistake. Always drip-acclimate new arrivals and quarantine for 2–4 weeks.
Tools & Resources
Accuracy note: This tool uses expert rules + FishBase.org data. Individual fish behavior varies — a aggressive individual Flowerhorn may act differently from its species average. Always observe, quarantine new arrivals for 2-4 weeks, and avoid overcrowding. If a pairing says CAUTION, start with a smaller group and a lid.