Can Hillstream Loach live with Serpae Tetra?
Case-by-case. Watch group sizes, tank size, and feeding zones.
Why Hillstream Loach and Serpae Tetra Don't Make an Easy Pair
They can coexist, but you need to manage the setup carefully. The temperature margin is tight — only 3°F of safe overlap, which leaves little room for thermostat drift.
Hillstream Loach
Sewellia lineolata
| Adult Size: | 2.5" |
| Temperament: | peaceful |
| Min Tank: | 20 gal |
| Temperature: | 64-75°F |
| pH Range: | 6.5-7.5 |
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 | Hillstream Loach | Serpae Tetra | Overlap |
|---|---|---|---|
| Temperature | 64-75°F | 72-79°F | 3°F ✓ |
| pH | 6.5-7.5 | 5.5-7.5 | 1.0 ✓ |
Compatibility Breakdown
Temperament Match: peaceful + semi-aggressive. Semi-aggressive → watch territory and feeding.
Score: 70.0/100 (GOOD ≥80, CAUTION ≥50, RISKY <50).
🔧 Tank Setup Requirements (for Both)
- Minimum tank: 20 gallons — sized for the larger fish in the pair.
- Temperature: keep it between 72°F and 75°F.
- pH: maintain 6.5 – 7.5.
- Hiding spots: essential for Hillstream Loach — 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 20+ gallons:
Algae wafers for herbivorous bottom feeders
Explore Related Checks
See what else works with these fish:
⚠️ Common Reasons This Pairing Fails in Practice
- Narrow temperature margin: Only 3°F of overlap means a stuck heater or seasonal temperature swing can push one species out of its comfort zone.
- 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.
- Mismatched feeding: Hillstream Loach is a herbivore while Serpae Tetra is a omnivore. Use targeted feeding zones and sinking vs. floating food to ensure both get proper nutrition.
Tools & Resources
Accuracy note: This tool uses expert rules + FishBase.org data. Individual fish behavior varies — a peaceful individual Hillstream Loach 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.