Can Clown Killifish and Neolamprologus Tretocephalus Live Together?

Clown Killifish is a peaceful species (2/10), while Neolamprologus Tretocephalus is semi-aggressive (8/10). This notable difference means Neolamprologus Tretocephalus may occasionally assert dominance over Clown Killifish.

Large aggression gap (6 points) between Clown Killifish and Neolamprologus Tretocephalus increases stress risk for the more peaceful fish.

In terms of spatial distribution, Clown Killifish prefers the Top (Surface) zone, whereas Neolamprologus Tretocephalus occupies the Bottom (Substrate) 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.

Additional behavioural considerations to keep in mind: Aggressive fish may bully and stress shy, slow-moving species.

Worth noting: Clown Killifish 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 Clown Killifish (5–7) and Neolamprologus Tretocephalus (8–9) do not overlap, making it impossible to satisfy both species simultaneously.

Hardness requirements are incompatible: Clown Killifish needs 1–8 dGH while Neolamprologus Tretocephalus requires 10–25 dGH.

To house Clown Killifish and Neolamprologus Tretocephalus together, plan for an aquarium of at least 150 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: Plants - Floating, Plants - Densely covered, Leaf Litter/Blackwater, Sand (Sifters), Smooth Gravel (Sensitive Barbels). Meeting these requirements will help both species thrive.

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

Clown Killifish and Neolamprologus Tretocephalus 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.