Can Chocolate Gourami and Mountain Rainbowfish Live Together?

Both Chocolate Gourami and Mountain Rainbowfish are peaceful species with an aggression score of 2/10. Their matching temperaments mean neither fish is likely to dominate the other in a shared aquarium.

Chocolate Gourami 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.

Additional behavioural considerations to keep in mind: Hyperactive swimmers can stress shy, slow-moving species through constant motion.

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

There is no temperature overlap between Chocolate Gourami (25–30°C) and Mountain Rainbowfish (17–24°C). This fundamental mismatch makes long-term cohabitation impractical.

The pH requirements of Chocolate Gourami (4–6.5) and Mountain Rainbowfish (7.4–8.5) do not overlap, making it impossible to satisfy both species simultaneously.

Hardness requirements are incompatible: Chocolate Gourami needs 0–5 dGH while Mountain Rainbowfish requires 8–20 dGH.

To house Chocolate Gourami and Mountain Rainbowfish together, plan for an aquarium of at least 110 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: Leaf Litter/Blackwater, Plants - Densely covered, Plants - Floating, Driftwood (Digestion/Hiding). Meeting these requirements will help both species thrive.

Chocolate Gourami 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.

Chocolate Gourami 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.