Can Lyretail Killifish and Weeksi Bichir Live Together?

Lyretail Killifish is a generally mild-mannered species (3/10), while Weeksi Bichir is moderately assertive (6/10). This modest difference means Weeksi Bichir may occasionally assert dominance over Lyretail Killifish.

In terms of spatial distribution, Lyretail Killifish prefers the Top (Surface) and Middle (Open Water) zones, whereas Weeksi Bichir 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.

There is a critical concern: 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..

Additional behavioural considerations to keep in mind: Shrimp eaters may also prey on very small nano fish.

Worth noting: Weeksi Bichir is nocturnal and will be most active after lights-out, naturally reducing daytime encounters. Also, Lyretail Killifish is a known jumper, so a tight-fitting lid is essential.

The safe temperature window for both species falls between 24°C and 26°C. Aim for the midpoint of this range (around 25.0°C) for optimal comfort.

Both fish can tolerate a pH between 6 and 7. Maintaining a stable value within this band is more important than hitting an exact number.

For general hardness, the shared comfort zone is 5–10 dGH. Regular testing will ensure conditions stay within this range.

To house Lyretail Killifish and Weeksi Bichir together, plan for an aquarium of at least 470 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 - Densely covered, Plants - Floating, Leaf Litter/Blackwater, Sand (Sifters), Smooth Gravel (Sensitive Barbels), Driftwood (Digestion/Hiding). 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.

Lyretail Killifish and Weeksi Bichir 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.

Feeding time deserves special attention with this pairing. Weeksi Bichir is a known shrimp eater and may prey on small invertebrates or nano fish like Lyretail Killifish.