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

Chuco Cichlid is a semi-aggressive species (7/10), while Rachov's Killifish (Annual) is generally mild-mannered (3/10). This notable difference means Chuco Cichlid may occasionally assert dominance over Rachov's Killifish (Annual).

Chuco Cichlid 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: 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.

To improve the chances of a peaceful coexistence in this community tank: Provide a significantly larger tank (at least 50% more volume than the minimum) to allow both Chuco Cichlid and Rachov's Killifish (Annual) to establish separate territories. Add plenty of line-of-sight breaks using driftwood, rocks, and dense planting to reduce territorial confrontations. A larger aquarium with ample hiding spots can help diffuse aggression and give the less dominant fish space to retreat.

The safe temperature window for both species falls between 24°C and 26°C. Aim for the midpoint of this range (around 25.0°C) for optimal comfort.

Both fish can tolerate a pH between 7 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 10–12 dGH. Regular testing will ensure conditions stay within this range.

To house Chuco Cichlid and Rachov's Killifish (Annual) together, plan for an aquarium of at least 450 litres with a minimum length of 120 cm. This recommendation combines the stricter species minimums with a community-load allowance so the pairing has realistic long-term space and filtration headroom.

Because this pairing requires extra vigilance, include plenty of hiding spots — caves, driftwood, and dense plant clusters — so the less dominant fish can retreat when needed.

Specific environmental needs for this combination include: Sand (Sifters), Smooth Gravel (Sensitive Barbels), Soil / Nutrient Rich, Leaf Litter/Blackwater, Plants - Densely covered. Meeting these requirements will help both species thrive.

Note a potential conflict in setup requirements: Chuco Cichlid requires Sand (Sifters), while Rachov's Killifish (Annual) requires Soil / Nutrient Rich. These substrate types may be difficult to provide simultaneously. Chuco Cichlid requires Smooth Gravel (Sensitive Barbels), while Rachov's Killifish (Annual) requires Soil / Nutrient Rich. These substrate types may be difficult to provide simultaneously. Chuco Cichlid 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.

Chuco Cichlid prefers High (River/Stream) flow while Rachov's Killifish (Annual) needs Low (Still Water) flow. Consider positioning filter outlets and using baffles to create zones of different current intensity within the same tank.

This pairing usually fails when the tank is treated like a standard mixed community and the caution flags are ignored. Chuco Cichlid and Rachov's Killifish (Annual) need extra room, more cover, and closer observation during the first few weeks so small aggression, feeding, or territory issues do not snowball into a long-term problem.

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