Can Beckford's Pencilfish and Brevis Shelldweller Live Together?

Beckford's Pencilfish is a peaceful species (2/10), while Brevis Shelldweller is moderately assertive (5/10). This modest difference means Brevis Shelldweller may occasionally assert dominance over Beckford's Pencilfish.

In terms of spatial distribution, Beckford's Pencilfish prefers the Top (Surface) and Middle (Open Water) zones, whereas Brevis Shelldweller 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: Beckford's Pencilfish 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 Beckford's Pencilfish (5–7.5) and Brevis Shelldweller (8–9) 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 Beckford's Pencilfish and Brevis Shelldweller together, plan for an aquarium of at least 60 litres with a minimum length of 60 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, Plants - Floating, Leaf Litter/Blackwater, Sand (Sifters), Shells (Breeding/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.

Beckford's Pencilfish and Brevis Shelldweller 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.