Can Black Sail Cory live with Swordtail?
Caution — with care
Why
- No overlapping water hardness: Black Sail Cory wants 2–10 dGH but Swordtail wants 12–30 dGH.
- Only a narrow pH overlap — keep both around 7–7.
- Swordtail is semi-aggressive — give the peaceful Black Sail Cory plenty of space, cover and broken sight lines.
- Large size gap (Swordtail 5.5" vs Black Sail Cory 2") — watch that the smaller one gets its share at feeding time.
Sweet spot: both do well at 75–82°F and pH 7–7 — aim there.
Side-by-side
| Black Sail Cory | Swordtail | |
|---|---|---|
| Temperature | 75–82°F | 72–82°F |
| pH | 5.5–7 | 7–8.4 |
| Hardness (GH) | 2–10 dGH | 12–30 dGH |
| Adult size | 2" | 5.5" |
| Temperament | Peaceful | Semi-aggressive |
| Min tank | 20 gal | 29 gal |
Together, plan on at least 29 gallons.
How to make it work
- Target the overlapping water-parameter range and acclimate slowly.
- Use a larger, well-decorated tank with sightline breaks, keep everyone well-fed, and add the calmer fish first.
Sort it with: GH remineraliser
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Design a tank with Black Sail Cory, Swordtail →Everything compatible with Black Sail Cory · …with Swordtail