Can Arapaima and Delhezi Bichir (Armored Bichir) Live Together?

Arapaima is a semi-aggressive species (7/10), while Delhezi Bichir (Armored Bichir) is moderately assertive (6/10). This modest difference means Arapaima may occasionally assert dominance over Delhezi Bichir (Armored Bichir).

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

Worth noting: Delhezi Bichir (Armored Bichir) is nocturnal and will be most active after lights-out, naturally reducing daytime encounters. Also, Arapaima is a known jumper, so a tight-fitting lid is essential.

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 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 Delhezi Bichir (Armored Bichir) 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.

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), Driftwood (Digestion/Hiding). 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.