Can Arapaima and White Cloud Mountain Minnow Live Together?

Arapaima is a semi-aggressive species (7/10), while White Cloud Mountain Minnow is peaceful (1/10). This notable difference means Arapaima may occasionally assert dominance over White Cloud Mountain Minnow.

Large aggression gap (6 points) between Arapaima and White Cloud Mountain Minnow increases stress risk for the more peaceful fish.

Arapaima and White Cloud Mountain Minnow 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.

There is a critical concern: the Piscivore (Eats small/nano fish) behaviour of one fish directly conflicts with the Nano / Bite-sized (Predation Risk) trait of the other — piscivorous fish will prey on nano-sized tank mates..

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

There is no temperature overlap between Arapaima (24–30°C) and White Cloud Mountain Minnow (14–22°C). This fundamental mismatch makes long-term cohabitation impractical.

Both fish can tolerate a pH between 6 and 7.5. 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 Arapaima and White Cloud Mountain Minnow 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: Plants - Densely covered, Smooth Gravel (Sensitive Barbels). Meeting these requirements will help both species thrive.

Note a potential conflict in setup requirements: Arapaima is a plant destroyer, which conflicts with White Cloud Mountain Minnow's requirement for live plants. Compromise where possible or prioritise the more critical need.

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