Can Cardinal Tetra and Shell Dweller (Multi) Live Together?

Cardinal Tetra is a peaceful species (1/10), while Shell Dweller (Multi) is moderately assertive (6/10). This notable difference means Shell Dweller (Multi) may occasionally assert dominance over Cardinal Tetra.

In terms of spatial distribution, Cardinal Tetra prefers the Middle (Open Water) zone, whereas Shell Dweller (Multi) 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.

The safe temperature window for both species falls between 24°C and 27°C. Aim for the midpoint of this range (around 25.5°C) for optimal comfort.

The pH requirements of Cardinal Tetra (4–7) and Shell Dweller (Multi) (7.8–9) do not overlap, making it impossible to satisfy both species simultaneously.

Hardness requirements are incompatible: Cardinal Tetra needs 1–8 dGH while Shell Dweller (Multi) requires 10–25 dGH.

To house Cardinal Tetra and Shell Dweller (Multi) together, plan for an aquarium of at least 66 litres with a minimum length of 60 cm. This accounts for the larger species' space requirements with an additional 20 % buffer to reduce territorial tension.

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: Leaf Litter/Blackwater, Driftwood (Digestion/Hiding), Plants - Densely covered, 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.