Can Chinese Algae Eater (CAE) and Dusky Millions Fish Live Together?

Chinese Algae Eater (CAE) is a semi-aggressive species (8/10), while Dusky Millions Fish is peaceful (2/10). This notable difference means Chinese Algae Eater (CAE) may occasionally assert dominance over Dusky Millions Fish.

Large aggression gap (6 points) between Chinese Algae Eater (CAE) and Dusky Millions Fish increases stress risk for the more peaceful fish.

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

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 Chinese Algae Eater (CAE) and Dusky Millions Fish 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. Keep fin nippers in larger groups to distribute nipping behaviour among conspecifics rather than tank mates.

The safe temperature window for both species falls between 22°C and 24°C. Aim for the midpoint of this range (around 23.0°C) for optimal comfort.

Both fish can tolerate a pH between 7 and 8. Maintaining a stable value within this band is more important than hitting an exact number.

For general hardness, the shared comfort zone is 8–15 dGH. Regular testing will ensure conditions stay within this range.

To house Chinese Algae Eater (CAE) and Dusky Millions Fish 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: Smooth Gravel (Sensitive Barbels), Plants - Densely covered, Plants - Floating, Established Algae (Otocinclus). Meeting these requirements will help both species thrive.

Chinese Algae Eater (CAE) prefers High (River/Stream) flow while Dusky Millions Fish 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. Chinese Algae Eater (CAE) and Dusky Millions Fish 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.