Can Arfak Rainbowfish and Kuhli Loach Live Together?

Arfak Rainbowfish is a peaceful species (2/10), while Kuhli Loach is peaceful (0/10). This modest difference means Arfak Rainbowfish may occasionally assert dominance over Kuhli Loach.

In terms of spatial distribution, Arfak Rainbowfish prefers the Middle (Open Water) and Top (Surface) zones, whereas Kuhli 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.

Additional behavioural considerations to keep in mind: Hyperactive swimmers can stress shy, slow-moving species through constant motion.

Worth noting: Kuhli Loach is nocturnal and will be most active after lights-out, naturally reducing daytime encounters. Also, Arfak Rainbowfish is a known jumper, so a tight-fitting lid is essential.

To improve the chances of a peaceful coexistence in this community tank: 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 28°C. Aim for the midpoint of this range (around 26.0°C) for optimal comfort.

Both fish can tolerate a pH between 7 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 5–10 dGH. Regular testing will ensure conditions stay within this range.

To house Arfak Rainbowfish and Kuhli Loach together, plan for an aquarium of at least 200 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: Plants - lighly covered, Smooth Gravel (Sensitive Barbels), Sand (Sifters), Leaf Litter/Blackwater, Plants - Densely covered. Meeting these requirements will help both species thrive.

Arfak Rainbowfish prefers High (River/Stream) flow while Kuhli Loach needs Low (Still Water) flow. Consider positioning filter outlets and using baffles to create zones of different current intensity within the same tank.