How Many Black Ghost Knifefish in a 125-Gallon Tank?
In a 125-gallon tank, plan on about 1–2 Black Ghost Knifefish, leaving room for tankmates and filtration headroom.
Why
Stocking is driven by adult size and waste output, not just fish count. Black Ghost Knifefish reaches about 18" with a heavy bioload, and needs 73–82°F water at pH 6–7.5. Always cycle the tank and test water before adding livestock.
| Adult size | 18" |
|---|---|
| Minimum tank | 120 gallons |
| Temperature | 73–82°F |
| pH | 6–7.5 |
| Temperament | Semi-aggressive |
| Schooling | No |
| Diet | Carnivore |
| Care level | Moderate |
| Origin | South America |
More fish for a 125-gallon tank → Black Ghost Knifefish tankmates →