Can Arapaima and Gold Nugget Pleco (L018) Live Together?

Arapaima is a semi-aggressive species (7/10), while Gold Nugget Pleco (L018) is moderately assertive (6/10). This modest difference means Arapaima may occasionally assert dominance over Gold Nugget Pleco (L018).

In terms of spatial distribution, Arapaima prefers the Top (Surface) and Middle (Open Water) zones, whereas Gold Nugget Pleco (L018) 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.

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

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

To improve the chances of a peaceful coexistence in this community tank: Provide a significantly larger tank (at least 50% more volume than the minimum) to allow both Arapaima and Gold Nugget Pleco (L018) to establish separate territories. Add plenty of line-of-sight breaks using driftwood, rocks, and dense planting to reduce territorial confrontations. 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 27°C and 30°C. Aim for the midpoint of this range (around 28.5°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 2–12 dGH. Regular testing will ensure conditions stay within this range.

To house Arapaima and Gold Nugget Pleco (L018) 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: Driftwood (Digestion/Hiding), Smooth Gravel (Sensitive Barbels), Established Algae (Otocinclus). Meeting these requirements will help both species thrive.

Arapaima prefers Low (Still Water) flow while Gold Nugget Pleco (L018) needs High (River/Stream) flow. Consider positioning filter outlets and using baffles to create zones of different current intensity within the same tank.