Can Fairy Cichlid (Brichardi) and Marbled Hatchetfish Live Together?

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

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

In terms of spatial distribution, Fairy Cichlid (Brichardi) prefers the Middle (Open Water) and Bottom (Substrate) zones, whereas Marbled Hatchetfish occupies the Top (Surface) 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: Aggressive fish may bully and stress shy, slow-moving species.

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

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 Fairy Cichlid (Brichardi) (8–9) and Marbled Hatchetfish (5.5–7.5) do not overlap, making it impossible to satisfy both species simultaneously.

For general hardness, the shared comfort zone is 10–12 dGH. Regular testing will ensure conditions stay within this range.

To house Fairy Cichlid (Brichardi) and Marbled Hatchetfish 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: Sand (Sifters), Smooth Gravel (Sensitive Barbels), Plants - Floating, Leaf Litter/Blackwater. 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.

Fairy Cichlid (Brichardi) and Marbled Hatchetfish 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.