Can Demasoni Cichlid (Mbuna) and Marbled Hatchetfish Live Together?

Demasoni Cichlid (Mbuna) is a highly aggressive species (9/10), while Marbled Hatchetfish is peaceful (1/10). This notable difference means Demasoni Cichlid (Mbuna) may occasionally assert dominance over Marbled Hatchetfish.

Large aggression gap (8 points) between Demasoni Cichlid (Mbuna) and Marbled Hatchetfish increases stress risk for the more peaceful fish.

In terms of spatial distribution, Demasoni Cichlid (Mbuna) prefers the Bottom (Substrate) and Middle (Open Water) 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. Hyperactive swimmers can stress shy, slow-moving species through constant motion.

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 28°C. Aim for the midpoint of this range (around 26.0°C) for optimal comfort.

The pH requirements of Demasoni Cichlid (Mbuna) (7.6–8.6) 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. An aquarium test kit is recommended for monitoring.

To house Demasoni Cichlid (Mbuna) and Marbled Hatchetfish together, plan for an aquarium of at least 240 litres with a minimum length of 120 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: Sand (Sifters), Established Algae (Otocinclus), Plants - Floating, Leaf Litter/Blackwater. Meeting these requirements will help both species thrive.

Demasoni Cichlid (Mbuna) prefers High (River/Stream) flow while Marbled Hatchetfish needs Low (Still Water) flow. Consider positioning filter outlets and using baffles to create zones of different current intensity within the same tank.