Can Kabia rainbowfish and Northern Mountain Swordtail Live Together?

Kabia rainbowfish is a peaceful species (2/10), while Northern Mountain Swordtail is generally mild-mannered (3/10). This modest difference means Northern Mountain Swordtail may occasionally assert dominance over Kabia rainbowfish.

Kabia rainbowfish and Northern Mountain Swordtail both frequent the Top (Surface) and Middle (Open Water) region of the setup. This overlap can increase competition for space, so providing ample room and cover is important to keep both species comfortable.

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

The safe temperature window for both species falls between 24°C and 25°C. Aim for the midpoint of this range (around 24.5°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 8–15 dGH. Regular testing will ensure conditions stay within this range.

To house Kabia rainbowfish and Northern Mountain Swordtail together, plan for an aquarium of at least 150 litres with a minimum length of 100 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: Plants - Densely covered, Plants - lighly covered. Meeting these requirements will help both species thrive.

Kabia rainbowfish prefers Low (Still Water) flow while Northern Mountain Swordtail needs High (River/Stream) flow. Consider positioning filter outlets and using baffles to create zones of different current intensity within the same tank.

This pairing usually fails when the tank is treated like a standard mixed community and the caution flags are ignored. Kabia rainbowfish and Northern Mountain 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.