Can African Knifefish and Scat (Brackish) Live Together?

African Knifefish is a moderately assertive species (5/10), while Scat (Brackish) is generally mild-mannered (4/10). This modest difference means African Knifefish may occasionally assert dominance over Scat (Brackish).

African Knifefish and Scat (Brackish) both frequent the Middle (Open Water) and Bottom (Substrate) region of the setup. This overlap can increase competition for space, so providing ample room and cover is important to keep both species comfortable.

Additional behavioural considerations to keep in mind: Hyperactive swimmers can stress shy, slow-moving species through constant motion. Aggressive eaters may outcompete shy fish for food, leading to malnutrition.

Worth noting: African Knifefish is nocturnal and will be most active after lights-out, naturally reducing daytime encounters.

The safe temperature window for both species falls between 23°C and 28°C. Aim for the midpoint of this range (around 25.5°C) for optimal comfort.

Both fish can tolerate a pH between 7.5 and 7.5. Maintaining a stable value within this band is more important than hitting an exact number.

For general hardness, the shared comfort zone is 12–15 dGH. Regular testing will ensure conditions stay within this range.

Crucially, these species require different water types — one needs freshwater while the other requires brackish conditions. This is a hard barrier to keeping them together.

To house African Knifefish and Scat (Brackish) together, plan for an aquarium of at least 474 litres with a minimum length of 150 cm. This recommendation combines the stricter species minimums with a community-load allowance so the pairing has realistic long-term space and filtration headroom.

Providing a mix of open swimming space and sheltered areas with rocks, driftwood, or plants will keep both species comfortable and allow natural behaviour.

Specific environmental needs for this combination include: Driftwood (Digestion/Hiding), Smooth Gravel (Sensitive Barbels), Plants - Floating, Sand (Sifters), Established Algae (Otocinclus). Meeting these requirements will help both species thrive.

African Knifefish prefers Low (Still Water) flow while Scat (Brackish) needs High (River/Stream) flow. Consider positioning filter outlets and using baffles to create zones of different current intensity within the same tank.

Feeding time deserves special attention with this pairing. Scat (Brackish) is an aggressive eater that may prevent African Knifefish from getting enough food.

Because Scat (Brackish) is a fast, competitive feeder, consider using sinking pellets or feeding at opposite ends of the setup to ensure African Knifefish receives an adequate share.