Compatibility Overview
Silver Arowana and Threadfin Rainbowfish 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 | Silver Arowana | Threadfin Rainbowfish | Verdict |
|---|---|---|---|
| Temperature | 72–86°F | 72–82°F | ✅ 72–82°F |
| pH Range | 6.0–7.5 | 6.5–7.5 | ✅ 6.5–7.5 |
| Temperament | semi | semi | ⚠️ Monitor |
| Adult Size | 19.7 in | 2.0 in | ❌ 10× difference |
| Min. Group | 1+ | 1+ | See below |
| Min. Tank Size | 100 gallons (for both species) | — | |
✅ Compatibility Positives
❌ Incompatibility Reasons
Species Profiles
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.
→ Full Silver Arowana care guide
Threadfin Rainbowfish — Aquarium species
The Threadfin Rainbowfish is a popular choice for freshwater aquariums due to its vibrant colors and peaceful nature. It requires a well-maintained tank with plenty of swimming space and a moderate water flow. These fish are not known to be aggressive and can be kept in community tanks with other peaceful species. Regular water changes and a balanced diet ar
Frequently Asked Questions
Can Silver Arowana live with Threadfin Rainbowfish?
Generally not recommended. Silver Arowana and Threadfin Rainbowfish 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 Silver Arowana and Threadfin Rainbowfish together?
A minimum of 100 gallons is recommended for keeping Silver Arowana and Threadfin Rainbowfish together. A larger tank improves water stability and reduces territorial conflict.
What temperature suits both Silver Arowana and Threadfin Rainbowfish?
72–82°F
Is a Silver Arowana aggressive toward a Threadfin Rainbowfish?
Silver Arowana is semi and Threadfin Rainbowfish 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 | 100/100 |
| Ph | 100/100 |
| Temperament | 62/100 |
| Adult Size | 8/100 |
| Swim Zone | 68/100 |
| 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. |