Can Cardinal Tetra and Fairy Cichlid (Brichardi) Live Together?

Cardinal Tetra is a peaceful species (1/10), while Fairy Cichlid (Brichardi) is semi-aggressive (8/10). This notable difference means Fairy Cichlid (Brichardi) may occasionally assert dominance over Cardinal Tetra.

Large aggression gap (7 points) between Cardinal Tetra and Fairy Cichlid (Brichardi) increases stress risk for the more peaceful fish.

Cardinal Tetra and Fairy Cichlid (Brichardi) both frequent the 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.

Additional behavioural considerations to keep in mind: Aggressive fish may bully and stress shy, slow-moving species.

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 Fairy Cichlid (Brichardi) (8–9) do not overlap, making it impossible to satisfy both species simultaneously.

Hardness requirements are incompatible: Cardinal Tetra needs 1–8 dGH while Fairy Cichlid (Brichardi) requires 10–25 dGH.

To house Cardinal Tetra and Fairy Cichlid (Brichardi) together, plan for an aquarium of at least 110 litres with a minimum length of 75 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: Leaf Litter/Blackwater, Driftwood (Digestion/Hiding), Plants - Densely covered, Sand (Sifters), Smooth Gravel (Sensitive Barbels). 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.

Cardinal Tetra and Fairy Cichlid (Brichardi) 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.