Can Blue Back Blue Eye and Boeseman's Rainbowfish Live Together?

Both Blue Back Blue Eye and Boeseman's Rainbowfish are peaceful species with an aggression score of 2/10. Their matching temperaments mean neither fish is likely to dominate the other in a shared aquarium.

Blue Back Blue Eye and Boeseman's Rainbowfish both frequent the Top (Surface) and Middle (Open Water) region of the setup. This overlap can increase competition for space, so providing ample room and cover is important to keep both species comfortable.

Worth noting: Blue Back Blue Eye is a known jumper, so a tight-fitting lid is essential.

The safe temperature window for both species falls between 26°C and 30°C. Aim for the midpoint of this range (around 28.0°C) for optimal comfort.

Both fish can tolerate a pH between 7 and 8.1. Maintaining a stable value within this band is more important than hitting an exact number.

For general hardness, the shared comfort zone is 10–19 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 Boeseman's Rainbowfish together, plan for an aquarium of at least 200 litres with a minimum length of 120 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), Plants - lighly covered. 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.