Compatibility Overview
Black Ghost Knifefish and Silver Arowana can generally share an aquarium with appropriate planning. Both species prefer overlapping temperature and pH ranges, and neither poses a major aggression risk to the other. A minimum 100-gallon tank is recommended to provide adequate territory and water volume for both species.
| Factor | Black Ghost Knifefish | Silver Arowana | Verdict |
|---|---|---|---|
| Temperature | 72–82°F | 72–86°F | ✅ 72–82°F |
| pH Range | 6.0–7.0 | 6.0–7.5 | ✅ 6.0–7.0 |
| Temperament | semi | semi | ⚠️ Monitor |
| Adult Size | 23.6 in | 19.7 in | ✅ Similar |
| Min. Group | 1+ | 1+ | See below |
| Min. Tank Size | 100 gallons (for both species) | — | |
✅ Compatibility Positives
⚠️ Caution Points
Species Profiles
Black Ghost Knifefish — Aquarium species
The Black Ghost Knifefish is a unique and elegant addition to the aquarium. With a lifespan of 5-8 years, it requires a minimum tank size of 200 liters. It is a solitary fish with a low aggression level and moderate activity. Its slender body and silver-blue coloration make it a captivating sight. Keep in mind that it may be sensitive to strong currents and
→ Full Black Ghost Knifefish 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 Black Ghost Knifefish live with Silver Arowana?
Yes, in a well-planned setup. Black Ghost Knifefish and Silver Arowana can generally share an aquarium with appropriate planning. Both species prefer overlapping temperature and pH ranges, and neither poses a major aggression risk to the other. A minimum 100-gallon tank is recommended to provide adequate territory and water volume for both species.
What tank size do I need for Black Ghost Knifefish and Silver Arowana together?
A minimum of 100 gallons is recommended for keeping Black Ghost Knifefish and Silver Arowana together. A larger tank improves water stability and reduces territorial conflict.
What temperature suits both Black Ghost Knifefish and Silver Arowana?
72–82°F
Is a Black Ghost Knifefish aggressive toward a Silver Arowana?
Black Ghost Knifefish is semi and Silver Arowana is semi. No major aggression issues are expected between these species.
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 | 100/100 |
| 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. |