Can Swordtail and Twig Catfish (Farlowella) Live Together?

Swordtail is a generally mild-mannered species (4/10), while Twig Catfish (Farlowella) is peaceful (1/10). This modest difference means Swordtail may occasionally assert dominance over Twig Catfish (Farlowella).

Swordtail and Twig Catfish (Farlowella) 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.

Additional behavioural considerations to keep in mind: Hyperactive swimmers can stress shy, slow-moving species through constant motion.

Worth noting: Swordtail is a known jumper, so a tight-fitting lid is essential.

The safe temperature window for both species falls between 23°C and 26°C. Aim for the midpoint of this range (around 24.5°C) for optimal comfort.

Both fish can tolerate a pH between 7 and 7.2. Maintaining a stable value within this band is more important than hitting an exact number.

Hardness requirements are incompatible: Swordtail needs 12–30 dGH while Twig Catfish (Farlowella) requires 3–10 dGH. An aquarium test kit is recommended for monitoring.

To house Swordtail and Twig Catfish (Farlowella) together, plan for an aquarium of at least 132 litres with a minimum length of 80 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: Plants - Densely covered, Driftwood (Digestion/Hiding), Established Algae (Otocinclus). 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.