Can Blackline Rasbora and Chinese Algae Eater (CAE) Live Together?

Blackline Rasbora is a peaceful species (1/10), while Chinese Algae Eater (CAE) is semi-aggressive (8/10). This notable difference means Chinese Algae Eater (CAE) may occasionally assert dominance over Blackline Rasbora.

Large aggression gap (7 points) between Blackline Rasbora and Chinese Algae Eater (CAE) increases stress risk for the more peaceful fish.

In terms of spatial distribution, Blackline Rasbora prefers the Middle (Open Water) and Top (Surface) zones, whereas Chinese Algae Eater (CAE) 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: Blackline Rasbora 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 Blackline Rasbora and Chinese Algae Eater (CAE) 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 22°C and 26°C. Aim for the midpoint of this range (around 24.0°C) for optimal comfort.

Both fish can tolerate a pH between 6 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 5–15 dGH. Regular testing will ensure conditions stay within this range.

To house Blackline Rasbora and Chinese Algae Eater (CAE) 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 - Densely covered, Driftwood (Digestion/Hiding), Leaf Litter/Blackwater, Smooth Gravel (Sensitive Barbels). Meeting these requirements will help both species thrive.

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

This pairing usually fails when the tank is treated like a standard mixed community and the caution flags are ignored. Blackline Rasbora and Chinese Algae Eater (CAE) 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.