Can Pacific Sturgeon and Swordtail Live Together?

Pacific Sturgeon is a generally mild-mannered species (3/10), while Swordtail is generally mild-mannered (4/10). This modest difference means Swordtail may occasionally assert dominance over Pacific Sturgeon.

In terms of spatial distribution, Pacific Sturgeon prefers the Bottom (Substrate) zone, whereas Swordtail occupies the Top (Surface) and Middle (Open Water) zones. Because they use different levels of the water column, territorial disputes are less likely and the tank will appear more balanced.

Worth noting: Swordtail is a known jumper, so a tight-fitting lid is essential.

The safe temperature window for both species falls between 21°C and 22°C. Aim for the midpoint of this range (around 21.5°C) for optimal comfort.

Both fish can tolerate a pH between 7 and 8. Maintaining a stable value within this band is more important than hitting an exact number.

For general hardness, the shared comfort zone is 12–20 dGH. Regular testing will ensure conditions stay within this range.

To house Pacific Sturgeon and Swordtail 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.

Because this pairing requires extra vigilance, include plenty of hiding spots — caves, driftwood, and dense plant clusters — so the less dominant fish can retreat when needed.

Specific environmental needs for this combination include: Sand (Sifters), Smooth Gravel (Sensitive Barbels), Plants - Densely covered. Meeting these requirements will help both species thrive.

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

This pairing usually fails when the tank is treated like a standard mixed community and the caution flags are ignored. Pacific Sturgeon and Swordtail need extra room, more cover, and closer observation during the first few weeks so small aggression, feeding, or territory issues do not snowball into a long-term problem.