Can Blue Back Blue Eye and Congo Bichir Live Together?

Blue Back Blue Eye is a peaceful species (2/10), while Congo Bichir is semi-aggressive (7/10). This notable difference means Congo Bichir may occasionally assert dominance over Blue Back Blue Eye.

In terms of spatial distribution, Blue Back Blue Eye prefers the Top (Surface) and Middle (Open Water) zones, whereas Congo 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: Congo Bichir is nocturnal and will be most active after lights-out, naturally reducing daytime encounters. Also, Blue Back Blue Eye is a known jumper, so a tight-fitting lid is essential.

The safe temperature window for both species falls between 24°C and 30°C. Aim for the midpoint of this range (around 27.0°C) for optimal comfort.

Both fish can tolerate a pH between 7 and 8. Maintaining a stable value within this band is more important than hitting an exact number.

For general hardness, the shared comfort zone is 10–20 dGH. Regular testing will ensure conditions stay within this range.

Crucially, these species require different water types — one needs freshwater while the other requires brackish conditions. This is a hard barrier to keeping them together.

To house Blue Back Blue Eye and Congo Bichir together, plan for an aquarium of at least 800 litres with a minimum length of 200 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: Driftwood (Digestion/Hiding), Sand (Sifters), Smooth Gravel (Sensitive Barbels). Meeting these requirements will help both species thrive.

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

Blue Back Blue Eye and Congo 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. Congo Bichir is a known shrimp eater and may prey on small invertebrates or nano fish like Blue Back Blue Eye.