Can Arapaima and Duboisi Cichlid (Tropheus) Live Together?

Arapaima is a semi-aggressive species (7/10), while Duboisi Cichlid (Tropheus) is semi-aggressive (8/10). This modest difference means Duboisi Cichlid (Tropheus) may occasionally assert dominance over Arapaima.

Both Arapaima and Duboisi Cichlid (Tropheus) are highly aggressive, increasing the risk of violent confrontations.

Arapaima and Duboisi Cichlid (Tropheus) 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: Arapaima is a known jumper, so a tight-fitting lid is essential.

The safe temperature window for both species falls between 24°C and 28°C. Aim for the midpoint of this range (around 26.0°C) for optimal comfort.

The pH requirements of Arapaima (6–7.5) and Duboisi Cichlid (Tropheus) (8–9) do not overlap, making it impossible to satisfy both species simultaneously.

For general hardness, the shared comfort zone is 10–15 dGH. Regular testing will ensure conditions stay within this range.

To house Arapaima and Duboisi Cichlid (Tropheus) together, plan for an aquarium of at least 15000 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.

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), Established Algae (Otocinclus), Smooth Gravel (Sensitive Barbels). Meeting these requirements will help both species thrive.

Both species do well with low (still water) water movement, so a standard filtration setup rated for the tank volume should suffice.