Can Redtail Splitfin and Uaru Live Together?

Redtail Splitfin is a moderately assertive species (6/10), while Uaru is generally mild-mannered (4/10). This modest difference means Redtail Splitfin may occasionally assert dominance over Uaru.

Redtail Splitfin and Uaru 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.

There is no temperature overlap between Redtail Splitfin (18–26°C) and Uaru (27–30°C). This fundamental mismatch makes long-term cohabitation impractical.

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

Hardness requirements are incompatible: Redtail Splitfin needs 10–25 dGH while Uaru requires 1–8 dGH.

To house Redtail Splitfin and Uaru together, plan for an aquarium of at least 400 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, Established Algae (Otocinclus), Driftwood (Digestion/Hiding), Sand (Sifters). Meeting these requirements will help both species thrive.

Note a potential conflict in setup requirements: Uaru is a plant destroyer, which conflicts with Redtail Splitfin'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.

Redtail Splitfin and Uaru 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.