Compatibility Overview
Black Ghost Knifefish and Percula Clownfish 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 | Black Ghost Knifefish | Percula Clownfish | Verdict |
|---|---|---|---|
| Temperature | 72–82°F | 75–82°F | ✅ 75–82°F |
| pH Range | 6.0–7.0 | 8.0–8.5 | ❌ No overlap |
| Temperament | semi | semi | ⚠️ Monitor |
| Adult Size | 23.6 in | 3.1 in | ❌ 8× difference |
| Min. Group | 1+ | 1+ | See below |
| Min. Tank Size | 100 gallons (for both species) | — | |
✅ Compatibility Positives
❌ Incompatibility Reasons
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
Percula Clownfish — Aquarium species
The Percula Clownfish, also known as the False Percula, is a popular beginner fish due to its hardiness and striking coloration. These fish are best kept in a saltwater tank with a minimum size of 30 gallons and compatible tankmates. They are peaceful, non-aggressive and do well in groups with other compatible species. Regular water quality maintenance is es
Frequently Asked Questions
Can Black Ghost Knifefish live with Percula Clownfish?
Generally not recommended. Black Ghost Knifefish and Percula Clownfish 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 Black Ghost Knifefish and Percula Clownfish together?
A minimum of 100 gallons is recommended for keeping Black Ghost Knifefish and Percula Clownfish together. A larger tank improves water stability and reduces territorial conflict.
What temperature suits both Black Ghost Knifefish and Percula Clownfish?
75–82°F
Is a Black Ghost Knifefish aggressive toward a Percula Clownfish?
Black Ghost Knifefish is semi and Percula Clownfish is semi. These animals require different water types and cannot share one aquarium.
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 | 0/100 |
| 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 | 100 gal | Only for the recommended minimum groups, mature filtration, and close monitoring. |
| Recommended community | 150 gal | Adds territory, swimming room, and a safer buffer for behavior. |
| Low-conflict setup | 180 gal | Best when keeping larger schools or reducing territorial pressure. |