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

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

Discus and Rachov's Killifish (Annual) 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 Discus (28–32°C) and Rachov's Killifish (Annual) (20–26°C). This fundamental mismatch makes long-term cohabitation impractical.

Both fish can tolerate a pH between 6 and 7.5. Maintaining a stable value within this band is more important than hitting an exact number.

For general hardness, the shared comfort zone is 4–12 dGH. Regular testing will ensure conditions stay within this range. An aquarium test kit is recommended for monitoring.

To house Discus and Rachov's Killifish (Annual) together, plan for an aquarium of at least 300 litres with a minimum length of 120 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), Driftwood (Digestion/Hiding), Leaf Litter/Blackwater, Soil / Nutrient Rich, Plants - Densely covered. Meeting these requirements will help both species thrive.

Note a potential conflict in setup requirements: Discus requires Sand (Sifters), while Rachov's Killifish (Annual) requires Soil / Nutrient Rich. These substrate types may be difficult to provide simultaneously. 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. Discus is a known shrimp eater and may prey on small invertebrates or nano fish like Rachov's Killifish (Annual).