Can Buccochromis rhoadesii and Cairns Rainbowfish Live Together?

Buccochromis rhoadesii is a semi-aggressive species (8/10), while Cairns Rainbowfish is peaceful (2/10). This notable difference means Buccochromis rhoadesii may occasionally assert dominance over Cairns Rainbowfish.

Large aggression gap (6 points) between Buccochromis rhoadesii and Cairns Rainbowfish increases stress risk for the more peaceful fish.

Buccochromis rhoadesii and Cairns Rainbowfish both frequent the 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: Cairns Rainbowfish is a known jumper, so a tight-fitting lid is essential.

The safe temperature window for both species falls between 24°C and 26°C. Aim for the midpoint of this range (around 25.0°C) for optimal comfort.

The pH requirements of Buccochromis rhoadesii (7.8–8.6) and Cairns Rainbowfish (6.5–7.6) do not overlap, making it impossible to satisfy both species simultaneously.

For general hardness, the shared comfort zone is 10–10 dGH. Regular testing will ensure conditions stay within this range.

To house Buccochromis rhoadesii and Cairns Rainbowfish together, plan for an aquarium of at least 600 litres with a minimum length of 180 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: Sand (Sifters), Smooth Gravel (Sensitive Barbels), Driftwood (Digestion/Hiding), Leaf Litter/Blackwater. 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.

Buccochromis rhoadesii and Cairns 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.