Can Clown Killifish and Otocinclus Live Together?

Clown Killifish is a peaceful species (2/10), while Otocinclus is peaceful (0/10). This modest difference means Clown Killifish may occasionally assert dominance over Otocinclus.

In terms of spatial distribution, Clown Killifish prefers the Top (Surface) zone, whereas Otocinclus occupies the Middle (Open Water) and Bottom (Substrate) zones. Because they use different levels of the water column, territorial disputes are less likely and the tank will appear more balanced.

Worth noting: Clown Killifish 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 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 Clown Killifish and Otocinclus together, plan for an aquarium of at least 46 litres with a minimum length of 45 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 - Floating, Plants - Densely covered, Leaf Litter/Blackwater, Established Algae (Otocinclus), Smooth Gravel (Sensitive Barbels), Driftwood (Digestion/Hiding). Meeting these requirements will help both species thrive.

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