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

Diamond Tetra is a peaceful species (2/10), while Fairy Cichlid (Brichardi) is semi-aggressive (8/10). This notable difference means Fairy Cichlid (Brichardi) may occasionally assert dominance over Diamond Tetra.

Large aggression gap (6 points) between Diamond Tetra and Fairy Cichlid (Brichardi) increases stress risk for the more peaceful fish.

Diamond 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.

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 Diamond Tetra (6–7.5) and Fairy Cichlid (Brichardi) (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 Diamond 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: Plants - Densely covered, Plants - Floating, Sand (Sifters), Smooth Gravel (Sensitive Barbels). Meeting these requirements will help both species thrive.

Both species do well with moderate (standard) water movement, so a standard filtration setup rated for the tank volume should suffice.

Diamond 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.