Can Australian Pearl Arowana and Tropheus Moorii Live Together?

Both Australian Pearl Arowana and Tropheus Moorii are highly aggressive species with an aggression score of 9/10. Their matching temperaments mean neither fish is likely to dominate the other in a shared aquarium.

Both Australian Pearl Arowana and Tropheus Moorii are highly aggressive, increasing the risk of violent confrontations.

In terms of spatial distribution, Australian Pearl Arowana prefers the Top (Surface) zone, whereas Tropheus Moorii occupies the Middle (Open Water) and Bottom (Substrate) zones. Because they use different levels of the water column, territorial disputes are less likely and the tank will appear more balanced.

Additional behavioural considerations to keep in mind: Two territorial species may clash over territory, especially in smaller tanks. Two aggressive species housed together increases risk of fighting.

Worth noting: Australian Pearl Arowana 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 Australian Pearl Arowana (6–7.5) and Tropheus Moorii (8–9.5) 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 Australian Pearl Arowana and Tropheus Moorii together, plan for an aquarium of at least 800 litres with a minimum length of 200 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: Smooth Gravel (Sensitive Barbels), Sand (Sifters), Established Algae (Otocinclus). 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.

Australian Pearl Arowana and Tropheus Moorii 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.