Can Mono Sebae (Brackish) and Swordtail Live Together?

Both Mono Sebae (Brackish) and Swordtail are generally mild-mannered species with an aggression score of 4/10. Their matching temperaments mean neither fish is likely to dominate the other in a shared aquarium.

Mono Sebae (Brackish) and Swordtail both frequent the 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: Swordtail is a known jumper, so a tight-fitting lid is essential.

The safe temperature window for both species falls between 24°C and 28°C. Aim for the midpoint of this range (around 26.0°C) for optimal comfort.

Both fish can tolerate a pH between 7.5 and 8.3. Maintaining a stable value within this band is more important than hitting an exact number.

For general hardness, the shared comfort zone is 12–30 dGH. Regular testing will ensure conditions stay within this range. An aquarium test kit is recommended for monitoring.

To house Mono Sebae (Brackish) and Swordtail together, plan for an aquarium of at least 480 litres with a minimum length of 150 cm. This accounts for the larger species' space requirements with an additional 20 % buffer to reduce territorial tension.

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: Sand (Sifters), Smooth Gravel (Sensitive Barbels), Plants - Densely covered. Meeting these requirements will help both species thrive.

Note a potential conflict in setup requirements: Mono Sebae (Brackish) is a plant destroyer, which conflicts with Swordtail's requirement for live plants. Compromise where possible or prioritise the more critical need.

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