Can Betta Macrostoma and Chinese Algae Eater (CAE) Live Together?

Betta Macrostoma is a moderately assertive species (6/10), while Chinese Algae Eater (CAE) is semi-aggressive (8/10). This modest difference means Chinese Algae Eater (CAE) may occasionally assert dominance over Betta Macrostoma.

Betta Macrostoma and Chinese Algae Eater (CAE) both frequent the Bottom (Substrate) region of the setup. This overlap can increase competition for space, so providing ample room and cover is important to keep both species comfortable.

There is a critical concern: the Shy / Slow Moving (Easily Stressed) behaviour of one fish directly conflicts with the Slime Coat Eater (Attacks Flat Fish) trait of the other — slime coat eaters target slow-moving fish, causing severe stress and health issues..

Additional behavioural considerations to keep in mind: Aggressive fish may bully and stress shy, slow-moving species. Hyperactive swimmers can stress shy, slow-moving species through constant motion. Two territorial species may clash over territory, especially in smaller tanks.

Worth noting: Betta Macrostoma is a known jumper, so a tight-fitting lid is essential.

The safe temperature window for both species falls between 22°C and 25°C. Aim for the midpoint of this range (around 23.5°C) for optimal comfort.

Both fish can tolerate a pH between 6 and 6. Maintaining a stable value within this band is more important than hitting an exact number.

For general hardness, the shared comfort zone is 5–5 dGH. Regular testing will ensure conditions stay within this range.

To house Betta Macrostoma 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.

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: Leaf Litter/Blackwater, Driftwood (Digestion/Hiding), Plants - Floating, Smooth Gravel (Sensitive Barbels). Meeting these requirements will help both species thrive.

Betta Macrostoma prefers Low (Still Water) flow while Chinese Algae Eater (CAE) needs High (River/Stream) flow. Consider positioning filter outlets and using baffles to create zones of different current intensity within the same tank.

Betta Macrostoma and Chinese Algae Eater (CAE) are the kind of pair that can look acceptable in a shop but become a maintenance problem at home. The main risk is not a single number in the chart; it is the way incompatible behavior, water needs, or pressure on space compounds over time once both fish are established in the same tank.