Serpae Tetra and Harlequin Rasbora Compatibility
Serpae Tetra and Harlequin Rasbora carry a clear risk: temperature ranges overlap at 72–82°F, yet temperament or size differences mean close supervision is essential. Plan on at least 20 gallons. Individual fish vary — observe behaviour during introduction.
Serpae Tetra vs Harlequin Rasbora at a glance
| Aspect | Serpae Tetra | Harlequin Rasbora |
|---|---|---|
| Adult size | ~1.6 in | ~1.8 in |
| Minimum tank | 20 gal | 10 gal |
| Temperature | 72–82°F | 72–82°F |
| pH | 6–7.5 | 6–7.5 |
| Temperament | semi-aggressive | peaceful |
| Swimming zone | middle | middle |
| Group size | 6+ | 6+ |
| Care level | easy | easy |
Overlap in temperature: 72–82°F. Overlap in pH: 6–7.5.
Why this verdict
- Temperature: Shared range of 72–82°F.
- Water parameters: Shared pH range of 6–7.5.
- Temperament: Serpae Tetra can be territorial; provide plants, sight breaks, and space.
- Adult size: Comparable adult sizes (~1.6" and ~1.8").
- Swimming zone: Both are middle-dwelling, but peaceful — sharing the layer is fine with cover.
- Schooling: Group sizes matter: Serpae Tetra: keep at least 6; Harlequin Rasbora: keep at least 6.
- Tank size: Plan for at least 20 gallons to satisfy both species.
Main risks
- Occasional chasing or fin nipping is possible.
Recommended tank
Plan on 20 gallons or larger for this pair. Suitable sizes: 20 gallon High, 20 gallon Long, 29 gallon.
Group sizes: Serpae Tetra: keep at least 6; Harlequin Rasbora: keep at least 6.
Sources
- FishBase — Scientific Database · Primary / scientific · https://www.fishbase.se/
- SeriouslyFish — Specialist Publication · High authority · https://www.seriouslyfish.com/
- Aquarium Forge editorial guidelines — Editorial Interpretation · Editorial interpretation
- FishBase — Scientific Database · Primary / scientific · https://www.fishbase.se/
- SeriouslyFish — Specialist Publication · High authority · https://www.seriouslyfish.com/
- Aquarium Forge editorial guidelines — Editorial Interpretation · Editorial interpretation
- Aquarium Forge editorial guidelines — Editorial Interpretation · Editorial interpretation
Compatibility verdicts are planning guidance, not guarantees — individual fish vary. Rule version 1.1 · Data reviewed: .
Frequently asked questions
Can Serpae Tetra and Harlequin Rasbora live together?
Our verdict is “Risky”. Serpae Tetra and Harlequin Rasbora carry a clear risk: temperature ranges overlap at 72–82°F, yet temperament or size differences mean close supervision is essential. Plan on at least 20 gallons. Individual fish vary — observe behaviour during introduction.
What tank size do Serpae Tetra and Harlequin Rasbora need?
Plan for at least 20 gallons so both species have their minimum space — Serpae Tetra needs 20+ gal and Harlequin Rasbora needs 10+ gal. Adding length and cover reduces stress further.
What temperature do Serpae Tetra and Harlequin Rasbora share?
Their comfortable ranges overlap at 72–82°F. Hold the tank near the middle of that band and avoid the extremes of either species' range.
What are the main risks keeping Serpae Tetra with Harlequin Rasbora?
Occasional chasing or fin nipping is possible.
How many Serpae Tetra and Harlequin Rasbora should I keep?
Serpae Tetra: keep at least 6; Harlequin Rasbora: keep at least 6. Group sizes matter for shoaling fish — too few and they become stressed and nippy.
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