Can discus live with black ghost knives?
Verdict
No
No. Discus and black ghost knives should not share a tank. An adult black ghost knife eats fish that fit in its mouth, and at 6 inches discus do.
What to watch
- Deal breakerAn adult black ghost knife eats fish that fit in its mouth, and at 6 inches discus do.
- Watch outThey only share 82°F. Keep the heater set there and steady.
- Watch outBlack ghost knives are much bigger and pushier than discus, which are slow and easy to bully at feeding time.
What works
- pH 6–7 suits both.
- They use different parts of the tank: discus the mid, black ghost knives the bottom.
Water side by side
Size to scale
Care at a glance
| Discus | Black ghost knife | |
|---|---|---|
| Temperature | 82–88 °F | 73–82 °F |
| pH | 5.5–7 | 6–8 |
| Adult size | 6.0 in | 15.0 in |
| Minimum tank | 55 gal | 125 gal |
| Temperament | Peaceful | Semi-aggressive |
| Swims at | Middle | Bottom |
| Group | Groups of 5+ | One per tank |
| Diet | Carnivore | Carnivore |
Better tank mates for discus
Better tank mates for black ghost knives
All black ghost knife tank mates
Questions
Can discus live with black ghost knives?
No. Discus and black ghost knives should not share a tank. An adult black ghost knife eats fish that fit in its mouth, and at 6 inches discus do.
What temperature suits both discus and black ghost knives?
82–82 °F. Discus need 82–88 °F, black ghost knives need 73–82 °F.
What size tank do discus and black ghost knives need together?
At least 125 gal, set by the black ghost knife. Add space for each extra fish.