Can Festivum and Mountain Rainbowfish Live Together?

Festivum is a generally mild-mannered species (4/10), while Mountain Rainbowfish is peaceful (2/10). This modest difference means Festivum may occasionally assert dominance over Mountain Rainbowfish.

Festivum and Mountain Rainbowfish 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: Festivum is a known jumper, so a tight-fitting lid is essential.

The safe temperature window for both species falls between 24°C and 24°C. Aim for the midpoint of this range (around 24.0°C) for optimal comfort.

The pH requirements of Festivum (5.5–7.2) and Mountain Rainbowfish (7.4–8.5) do not overlap, making it impossible to satisfy both species simultaneously.

For general hardness, the shared comfort zone is 8–12 dGH. Regular testing will ensure conditions stay within this range.

To house Festivum and Mountain Rainbowfish together, plan for an aquarium of at least 150 litres with a minimum length of 90 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), Plants - Floating. Meeting these requirements will help both species thrive.

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

Festivum and Mountain Rainbowfish 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.