Can Boeseman's Rainbowfish live with Serpae Tetra?
High risk due to water mismatch, aggression, or predation.
Why Boeseman's Rainbowfish and Serpae Tetra Don't Make an Easy Pair
The size gap is 2.5" — Boeseman's Rainbowfish (4.5") and Serpae Tetra (2.0"). A fish that fits in another fish's mouth will eventually end up there.
Boeseman's Rainbowfish
Melanotaenia boesemani
| Adult Size: | 4.5" |
| Temperament: | peaceful |
| Min Tank: | 30 gal |
| Temperature: | 75-82°F |
| pH Range: | 7.0-8.0 |
Serpae Tetra
Hyphessobrycon eques
| Adult Size: | 2.0" |
| Temperament: | semi-aggressive |
| Min Tank: | 20 gal |
| Temperature: | 72-79°F |
| pH Range: | 5.5-7.5 |
Water Parameter Overlap
| Parameter | Boeseman's Rainbowfish | Serpae Tetra | Overlap |
|---|---|---|---|
| Temperature | 75-82°F | 72-79°F | 4°F ✓ |
| pH | 7.0-8.0 | 5.5-7.5 | 0.5 ✓ |
Compatibility Breakdown
Temperament Match: peaceful + semi-aggressive. Semi-aggressive → watch territory and feeding.
⚠️ Size Predation Risk: Boeseman's Rainbowfish (4.5") vs Serpae Tetra (2.0"). A 2.5" gap — the larger fish will view the smaller fish as food.
Score: 40.0/100 (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 75°F and 79°F.
- pH: maintain 7.0 – 7.5.
- Hiding spots: essential for Boeseman's Rainbowfish — 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 rainbowfish
Explore Related Checks
See what else works with these fish:
⚠️ Common Reasons This Pairing Fails in Practice
- Size-based predation: The 2.5" size gap means the larger fish may eat the smaller one once it grows to full size. This is not fixable with more hiding spots.
- Overcrowding: Even compatible species fail in tanks that are too small. Double the species means double the bioload — 25% weekly water changes are the minimum.
- Inadequate acclimation: Adding both species on the same day without quarantine is a common mistake. Always drip-acclimate new arrivals and quarantine for 2–4 weeks.
Tools & Resources
Accuracy note: This tool uses expert rules + FishBase.org data. Individual fish behavior varies — a peaceful individual Boeseman's Rainbowfish 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.