Can Clown Killifish and Malawi Eyebiter Live Together?

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

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

Clown Killifish and Malawi Eyebiter both frequent the Top (Surface) region of the setup. This overlap can increase competition for space, so providing ample room and cover is important to keep both species comfortable.

There are critical concerns: the Nano / Bite-sized (Predation Risk) behaviour of one fish directly conflicts with the Piscivore (Eats small/nano fish) trait of the other — piscivorous fish will prey on nano-sized tank mates.. Additionally, the Shy / Slow Moving (Easily Stressed) behaviour of one fish directly conflicts with the Eye Biter (Attacks slow moving fish) trait of the other — eye biters attack slow-moving fish, risking permanent injury..

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 23°C and 27°C. Aim for the midpoint of this range (around 25.0°C) for optimal comfort.

The pH requirements of Clown Killifish (5–7) and Malawi Eyebiter (7.8–8.6) do not overlap, making it impossible to satisfy both species simultaneously.

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

To house Clown Killifish and Malawi Eyebiter together, plan for an aquarium of at least 475 litres with a minimum length of 150 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). 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 Malawi Eyebiter 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.