Can Rachov's Killifish (Annual) and Uaru Live Together?

Rachov's Killifish (Annual) is a generally mild-mannered species (3/10), while Uaru is generally mild-mannered (4/10). This modest difference means Uaru may occasionally assert dominance over Rachov's Killifish (Annual).

Rachov's Killifish (Annual) and Uaru both frequent the Middle (Open Water) and Bottom (Substrate) 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. Shrimp eaters may also prey on very small nano fish.

Worth noting: Rachov's Killifish (Annual) is a known jumper, so a tight-fitting lid is essential.

There is no temperature overlap between Rachov's Killifish (Annual) (20–26°C) and Uaru (27–30°C). This fundamental mismatch makes long-term cohabitation impractical.

Both fish can tolerate a pH between 6 and 7. Maintaining a stable value within this band is more important than hitting an exact number.

For general hardness, the shared comfort zone is 4–8 dGH. Regular testing will ensure conditions stay within this range. An aquarium test kit is recommended for monitoring.

To house Rachov's Killifish (Annual) and Uaru 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: Soil / Nutrient Rich, Leaf Litter/Blackwater, Plants - Densely covered, Driftwood (Digestion/Hiding), Sand (Sifters). Meeting these requirements will help both species thrive.

Note a potential conflict in setup requirements: Rachov's Killifish (Annual) requires Soil / Nutrient Rich, while Uaru requires Sand (Sifters). These substrate types may be difficult to provide simultaneously. Uaru is a plant destroyer, which conflicts with Rachov's Killifish (Annual)'s requirement for live plants. Compromise where possible or prioritise the more critical need.

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

Feeding time deserves special attention with this pairing. Uaru is a known shrimp eater and may prey on small invertebrates or nano fish like Rachov's Killifish (Annual).