Can Firemouth Cichlid live with Harlequin Rasbora?
High risk due to water mismatch, aggression, or predation.
Why Firemouth Cichlid and Harlequin Rasbora Don't Make an Easy Pair
The size gap is 4.0" — Firemouth Cichlid (6.0") and Harlequin Rasbora (2.0"). A fish that fits in another fish's mouth will eventually end up there.
Firemouth Cichlid
Thorichthys meeki
| Adult Size: | 6.0" |
| Temperament: | semi-aggressive |
| Min Tank: | 30 gal |
| Temperature: | 75-86°F |
| pH Range: | 6.5-8.0 |
Harlequin Rasbora
Trigonostigma heteromorpha
| Adult Size: | 2.0" |
| Temperament: | peaceful |
| Min Tank: | 10 gal |
| Temperature: | 73-79°F |
| pH Range: | 5.5-7.0 |
Water Parameter Overlap
| Parameter | Firemouth Cichlid | Harlequin Rasbora | Overlap |
|---|---|---|---|
| Temperature | 75-86°F | 73-79°F | 4°F ✓ |
| pH | 6.5-8.0 | 5.5-7.0 | 0.5 ✓ |
Compatibility Breakdown
Temperament Match: semi-aggressive + peaceful. Semi-aggressive → watch territory and feeding.
⚠️ Size Predation Risk: Firemouth Cichlid (6.0") vs Harlequin Rasbora (2.0"). A 4.0" gap — the larger fish will view the smaller fish as food.
Score: 40.0/100 (GOOD ≥80, CAUTION ≥50, RISKY <50).
🔧 Tank Setup Requirements (for Both)
- Minimum tank: 30 gallons — sized for the larger fish in the pair.
- Temperature: keep it between 75°F and 79°F.
- pH: maintain 6.5 – 7.0.
- Hiding spots: essential for Firemouth Cichlid — 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 30+ gallons:
Floating pellet for medium cichlids
Explore Related Checks
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Accuracy note: This tool uses expert rules + FishBase.org data. Individual fish behavior varies — a semi-aggressive individual Firemouth Cichlid 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.