Can Hillstream Loach live with Common Plecostomus?
Case-by-case. Watch group sizes, tank size, and feeding zones.
Why Hillstream Loach and Common Plecostomus 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 |
Common Plecostomus
Hypostomus plecostomus
| Adult Size: | 15.0" |
| Temperament: | peaceful |
| Min Tank: | 55 gal |
| Temperature: | 72-86°F |
| pH Range: | 6.5-7.8 |
Water Parameter Overlap
| Parameter | Hillstream Loach | Common Plecostomus | Overlap |
|---|---|---|---|
| Temperature | 64-75°F | 72-86°F | 3°F ✓ |
| pH | 6.5-7.5 | 6.5-7.8 | 1.0 ✓ |
Compatibility Breakdown
Temperament Match: peaceful + peaceful. Both peaceful → minimal conflict.
⚠️ Size Predation Risk: Hillstream Loach (2.5") vs Common Plecostomus (15.0"). A 12.5" gap — the larger fish will view the smaller fish as food.
Score: 50.0/100 (GOOD ≥80, CAUTION ≥50, RISKY <50).
🔧 Tank Setup Requirements (for Both)
- Minimum tank: 55 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 55+ gallons:
Sinking wafers for plecos and bottom feeders
Explore Related Checks
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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.