Can Red Tail Black Shark live with Swordtail?
These two species are usually compatible in community tanks.
Why Red Tail Black Shark and Swordtail Work
These two species overlap in both temperature (72–78°F overlap) and pH (7.0-7.5 overlap range). Their temperature tolerances are close enough, and neither fish pushes the pH so far outside the other's comfort zone that it creates chronic stress. The temperament match (semi-aggressive + semi-aggressive) is low-conflict. In a 30+ gallon tank with adequate hiding spots, these two can coexist with minimal problems.
Red Tail Black Shark
Epalzeorhynchos bicolor
| Adult Size: | 5.0" |
| Temperament: | semi-aggressive |
| Min Tank: | 30 gal |
| Temperature: | 72-80°F |
| pH Range: | 6.5-7.5 |
Swordtail
Xiphophorus helleri
| Adult Size: | 5.0" |
| Temperament: | semi-aggressive |
| Min Tank: | 20 gal |
| Temperature: | 72-78°F |
| pH Range: | 7.0-8.0 |
Water Parameter Overlap
| Parameter | Red Tail Black Shark | Swordtail | Overlap |
|---|---|---|---|
| Temperature | 72-80°F | 72-78°F | 6°F ✓ |
| pH | 6.5-7.5 | 7.0-8.0 | 0.5 ✓ |
Compatibility Breakdown
Temperament Match: semi-aggressive + semi-aggressive. Semi-aggressive → watch territory and feeding.
Score: 80.0/100 (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 72°F and 78°F.
- pH: maintain 7.0 – 7.5.
- Hiding spots: essential for Red Tail Black Shark — 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:
High-quality flake food for community fish
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 Red Tail Black Shark 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.