Compatibility Overview
Hillstream Loach and Silver Arowana are generally not recommended to be housed together. The issues listed above — whether water parameter incompatibility, predation risk, or aggression — create conditions where one or both fish are likely to suffer harm or chronic stress.
| Factor | Hillstream Loach | Silver Arowana | Verdict |
|---|---|---|---|
| Temperature | 64–73°F | 72–86°F | ⚠️ 72–73°F (narrow) |
| pH Range | 6.5–7.5 | 6.0–7.5 | ✅ 6.5–7.5 |
| Temperament | semi | semi | ⚠️ Monitor |
| Adult Size | 2.0 in | 19.7 in | ❌ 10× difference |
| Min. Group | 1+ | 1+ | See below |
| Min. Tank Size | 100 gallons (for both species) | — | |
✅ Compatibility Positives
❌ Incompatibility Reasons
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
Silver Arowana — Aquarium species
The Silver Arowana is a majestic and unique fish known for its striking appearance and size. It is a large, predatory fish that requires a spacious tank and specific water conditions. While not a community fish, it can be kept with compatible, larger species. They are sensitive to stress and require careful water quality management.
Frequently Asked Questions
Can Hillstream Loach live with Silver Arowana?
Generally not recommended. Hillstream Loach and Silver Arowana are generally not recommended to be housed together. The issues listed above — whether water parameter incompatibility, predation risk, or aggression — create conditions where one or both fish are likely to suffer harm or chronic stress.
What tank size do I need for Hillstream Loach and Silver Arowana together?
A minimum of 100 gallons is recommended for keeping Hillstream Loach and Silver Arowana together. A larger tank improves water stability and reduces territorial conflict.
What temperature suits both Hillstream Loach and Silver Arowana?
72–73°F (narrow)
Is a Hillstream Loach aggressive toward a Silver Arowana?
Hillstream Loach is semi and Silver Arowana is semi. The adult size gap creates a meaningful predation risk.
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 | 62/100 |
| Adult Size | 8/100 |
| 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 | 528 gal | Only for the recommended minimum groups, mature filtration, and close monitoring. |
| Recommended community | 750 gal | Adds territory, swimming room, and a safer buffer for behavior. |
| Low-conflict setup | 950 gal | Best when keeping larger schools or reducing territorial pressure. |