Can Clown Knifefish and Pacific Sturgeon Live Together?

Clown Knifefish is a semi-aggressive species (7/10), while Pacific Sturgeon is generally mild-mannered (3/10). This notable difference means Clown Knifefish may occasionally assert dominance over Pacific Sturgeon.

Clown Knifefish and Pacific Sturgeon both frequent the 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: Clown Knifefish is nocturnal and will be most active after lights-out, naturally reducing daytime encounters. Also, Clown Knifefish is a known jumper, so a tight-fitting lid is essential.

There is no temperature overlap between Clown Knifefish (24–28°C) and Pacific Sturgeon (10–22°C). This fundamental mismatch makes long-term cohabitation impractical.

Both fish can tolerate a pH between 6.5 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 5–15 dGH. Regular testing will ensure conditions stay within this range.

To house Clown Knifefish and Pacific Sturgeon together, plan for an aquarium of at least 20000 litres with a minimum length of 600 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: Smooth Gravel (Sensitive Barbels), Driftwood (Digestion/Hiding), Plants - Densely covered, Sand (Sifters). Meeting these requirements will help both species thrive.

Both species do well with moderate (standard) water movement, so a standard filtration setup rated for the tank volume should suffice.

Clown Knifefish and Pacific Sturgeon are the kind of pair that can look acceptable in a shop but become a maintenance problem at home. The main risk is not a single number in the chart; it is the way incompatible behavior, water needs, or pressure on space compounds over time once both fish are established in the same tank.

Feeding time deserves special attention with this pairing. Pacific Sturgeon is an aggressive eater that may prevent Clown Knifefish from getting enough food.

Because Pacific Sturgeon is a fast, competitive feeder, consider using sinking pellets or feeding at opposite ends of the setup to ensure Clown Knifefish receives an adequate share.