Compatibility Overview
Harlequin Rasbora and Swordtail can generally share an aquarium with appropriate planning. Both species prefer overlapping temperature and pH ranges, and neither poses a major aggression risk to the other. A minimum 75-gallon tank is recommended to provide adequate territory and water volume for both species.
| Factor | Harlequin Rasbora | Swordtail | Verdict |
|---|---|---|---|
| Temperature | 72–81°F | 65–80°F | ✅ 72–80°F |
| pH Range | 5.5–7.5 | 7.0–8.3 | ⚠️ 7.0–7.5 (narrow) |
| Temperament | peaceful | peaceful | ✅ Compatible |
| Adult Size | 1.75 in | 5 in | ⚠️ 2.9× difference |
| Min. Group | 8+ | 3+ | See below |
| Min. Tank Size | 75 gallons (for both species) | — | |
✅ Compatibility Positives
⚠️ Caution Points
Species Profiles
Harlequin Rasbora — Trigonostigma heteromorpha
Active mid-level schooling fish with a distinctive black triangular patch. One of the best all-around community tank fish.
→ Full Harlequin Rasbora care guide
Swordtail — Xiphophorus hellerii
Hardy livebearer with a distinctive elongated lower tail fin in males. Peaceful community fish that tolerate a wide temperature range.
Frequently Asked Questions
Can Harlequin Rasbora live with Swordtail?
Yes, in a well-planned setup. Harlequin Rasbora and Swordtail can generally share an aquarium with appropriate planning. Both species prefer overlapping temperature and pH ranges, and neither poses a major aggression risk to the other. A minimum 75-gallon tank is recommended to provide adequate territory and water volume for both species.
What tank size do I need for Harlequin Rasbora and Swordtail together?
A minimum of 75 gallons is recommended for keeping Harlequin Rasbora and Swordtail together. A larger tank improves water stability and reduces territorial conflict.
What temperature suits both Harlequin Rasbora and Swordtail?
72–80°F
Is a Harlequin Rasbora aggressive toward a Swordtail?
Harlequin Rasbora is peaceful and Swordtail is peaceful. Limited pH overlap (7.0–7.5) — maintain pH carefully within this narrow window.