Compatibility Overview
Harlequin Rasbora and Rainbow Shark 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 | Rainbow Shark | Verdict |
|---|---|---|---|
| Temperature | 72–81°F | 72–79°F | ✅ 72–79°F |
| pH Range | 5.5–7.5 | 6.5–7.5 | ✅ 6.5–7.5 |
| Temperament | peaceful | semi | ⚠️ Monitor |
| Adult Size | 1.75 in | 6 in | ⚠️ 3.4× difference |
| Min. Group | 8+ | 1+ | 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
Rainbow Shark — Epalzeorhynchos frenatum
Active bottom dweller that becomes territorial at maturity. One per tank; avoid other shark-like or bottom-dwelling species.
Frequently Asked Questions
Can Harlequin Rasbora live with Rainbow Shark?
Yes, in a well-planned setup. Harlequin Rasbora and Rainbow Shark 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 Rainbow Shark together?
A minimum of 75 gallons is recommended for keeping Harlequin Rasbora and Rainbow Shark together. A larger tank improves water stability and reduces territorial conflict.
What temperature suits both Harlequin Rasbora and Rainbow Shark?
72–79°F
Is a Harlequin Rasbora aggressive toward a Rainbow Shark?
Harlequin Rasbora is peaceful and Rainbow Shark is semi. Minor aggression possible from the semi-aggressive species; provide hiding spots.