Can African Arowana and MacCulloch's Rainbowfish (Dwarf Rainbowfish) Live Together?

African Arowana is a generally mild-mannered species (4/10), while MacCulloch's Rainbowfish (Dwarf Rainbowfish) is peaceful (2/10). This modest difference means African Arowana may occasionally assert dominance over MacCulloch's Rainbowfish (Dwarf Rainbowfish).

African Arowana and MacCulloch's Rainbowfish (Dwarf 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.

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

Worth noting: African Arowana is a known jumper, so a tight-fitting lid is essential.

To improve the chances of a peaceful coexistence in this community tank: A larger aquarium with ample hiding spots can help diffuse aggression and give the less dominant fish space to retreat.

The safe temperature window for both species falls between 24°C and 30°C. Aim for the midpoint of this range (around 27.0°C) for optimal comfort.

Both fish can tolerate a pH between 6.5 and 8. Maintaining a stable value within this band is more important than hitting an exact number.

For general hardness, the shared comfort zone is 5–15 dGH. Regular testing will ensure conditions stay within this range.

To house African Arowana and MacCulloch's Rainbowfish (Dwarf Rainbowfish) together, plan for an aquarium of at least 1500 litres with a minimum length of 250 cm. This recommendation combines the stricter species minimums with a community-load allowance so the pairing has realistic long-term space and filtration headroom.

Because this pairing requires extra vigilance, include plenty of hiding spots — caves, driftwood, and dense plant clusters — so the less dominant fish can retreat when needed.

Specific environmental needs for this combination include: Sand (Sifters), Smooth Gravel (Sensitive Barbels), Plants - Densely covered. 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.