Can Gardner's Killifish and Reticulated Hillstream Loach Live Together?

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

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

Worth noting: Gardner's Killifish is a known jumper, so a tight-fitting lid is essential.

The safe temperature window for both species falls between 20°C and 24°C. Aim for the midpoint of this range (around 22.0°C) for optimal comfort.

Both fish can tolerate a pH between 6.5 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 4–10 dGH. Regular testing will ensure conditions stay within this range. An aquarium test kit is recommended for monitoring.

To house Gardner's Killifish and Reticulated Hillstream Loach together, plan for an aquarium of at least 96 litres with a minimum length of 90 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 - Densely covered, Plants - Floating, Plants - lighly covered, Smooth Gravel (Sensitive Barbels), Established Algae (Otocinclus). Meeting these requirements will help both species thrive.

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