Compatibility Overview
Hillstream Loach and Otocinclus can potentially coexist, but the combination requires careful attention. Some combination of water parameter differences, size mismatch, or temperament issues make this pair challenging. A larger tank (minimum 29 gallons), dense planting, and close monitoring are essential.
| Factor | Hillstream Loach | Otocinclus | Verdict |
|---|---|---|---|
| Temperature | 64–73°F | 72–82°F | ⚠️ 72–73°F (narrow) |
| pH Range | 6.5–7.5 | 6.0–7.5 | ✅ 6.5–7.5 |
| Temperament | semi | peaceful | ⚠️ Monitor |
| Adult Size | 2.0 in | 1.5 in | ✅ Similar |
| Min. Group | 1+ | 4+ | See below |
| Min. Tank Size | 29 gallons (for both species) | — | |
✅ Compatibility Positives
⚠️ Caution Points
Species Profiles
Hillstream Loach — Aquarium species
Sewellia lineolata, known as the Hillstream Loach, is a fascinating species for aquarists. These fish require a well-oxygenated, clear water environment with plenty of hiding spots. With a lifespan of 7 years, they are a long-term commitment. Their olive green color and slender body shape add a unique aesthetic to the tank. Despite their moderate activity le
→ Full Hillstream Loach care guide
Otocinclus — Otocinclus spp.
Tiny algae-eating catfish that are peaceful with all species. Need established algae growth and biofilm; sensitive to ammonia.
Frequently Asked Questions
Can Hillstream Loach live with Otocinclus?
With significant caution and a larger tank. Hillstream Loach and Otocinclus can potentially coexist, but the combination requires careful attention. Some combination of water parameter differences, size mismatch, or temperament issues make this pair challenging. A larger tank (minimum 29 gallons), dense planting, and close monitoring are essential.
What tank size do I need for Hillstream Loach and Otocinclus together?
A minimum of 29 gallons is recommended for keeping Hillstream Loach and Otocinclus together. A larger tank improves water stability and reduces territorial conflict.
What temperature suits both Hillstream Loach and Otocinclus?
72–73°F (narrow)
Is a Hillstream Loach aggressive toward a Otocinclus?
Hillstream Loach is semi and Otocinclus is peaceful. Their preferred temperature ranges have little or no safe overlap.
Related Compatibility Guides
Compatibility score breakdown
The overall score is weighted across water chemistry, behavior, adult size, swimming zone, and social needs. A score is a planning aid—not a guarantee for individual fish.
| Factor | Score |
|---|---|
| Temperature | 11/100 |
| Ph | 100/100 |
| Temperament | 75/100 |
| Adult Size | 100/100 |
| Swim Zone | 92/100 |
| Social Needs | 92/100 |
Tank size scenarios
Use the scenario that matches the actual group sizes and temperament you plan to keep.
| Scenario | Tank | When it applies |
|---|---|---|
| Minimum viable | 29 gal | Only for the recommended minimum groups, mature filtration, and close monitoring. |
| Recommended community | 40 gal | Adds territory, swimming room, and a safer buffer for behavior. |
| Low-conflict setup | 75 gal | Best when keeping larger schools or reducing territorial pressure. |