Can Tanganyikan Clown Cichlid (Eretmodus) and Threadfin Rainbowfish Live Together?

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

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

In terms of spatial distribution, Tanganyikan Clown Cichlid (Eretmodus) prefers the Bottom (Substrate) zone, whereas Threadfin Rainbowfish occupies the Top (Surface) and Middle (Open Water) zones. Because they use different levels of the water column, territorial disputes are less likely and the tank will appear more balanced.

Worth noting: Threadfin Rainbowfish 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 Tanganyikan Clown Cichlid (Eretmodus) (8–9.5) and Threadfin Rainbowfish (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 Tanganyikan Clown Cichlid (Eretmodus) and Threadfin Rainbowfish 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: Smooth Gravel (Sensitive Barbels), Established Algae (Otocinclus), Plants - Densely covered, Plants - Floating. Meeting these requirements will help both species thrive.

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

Tanganyikan Clown Cichlid (Eretmodus) and Threadfin Rainbowfish 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.