Can Cardinal Tetra and Tanganyikan Clown Cichlid (Eretmodus) Live Together?

Cardinal Tetra is a peaceful species (1/10), while Tanganyikan Clown Cichlid (Eretmodus) is semi-aggressive (7/10). This notable difference means Tanganyikan Clown Cichlid (Eretmodus) may occasionally assert dominance over Cardinal Tetra.

Large aggression gap (6 points) between Cardinal Tetra and Tanganyikan Clown Cichlid (Eretmodus) increases stress risk for the more peaceful fish.

In terms of spatial distribution, Cardinal Tetra prefers the Middle (Open Water) zone, whereas Tanganyikan Clown Cichlid (Eretmodus) 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.

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 Cardinal Tetra (4–7) and Tanganyikan Clown Cichlid (Eretmodus) (8–9.5) do not overlap, making it impossible to satisfy both species simultaneously.

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

To house Cardinal Tetra and Tanganyikan Clown Cichlid (Eretmodus) together, plan for an aquarium of at least 100 litres with a minimum length of 90 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, Smooth Gravel (Sensitive Barbels), Established Algae (Otocinclus). Meeting these requirements will help both species thrive.

Cardinal Tetra prefers Low (Still Water) flow while Tanganyikan Clown Cichlid (Eretmodus) needs High (River/Stream) flow. Consider positioning filter outlets and using baffles to create zones of different current intensity within the same tank.

Cardinal Tetra and Tanganyikan Clown Cichlid (Eretmodus) 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.