Can Espei Rasbora (Lambchop Rasbora) and One-Spot Betta Live Together?

Espei Rasbora (Lambchop Rasbora) is a peaceful species (1/10), while One-Spot Betta is moderately assertive (6/10). This notable difference means One-Spot Betta may occasionally assert dominance over Espei Rasbora (Lambchop Rasbora).

Espei Rasbora (Lambchop Rasbora) and One-Spot Betta both frequent the Middle (Open Water) and Top (Surface) 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 Nano / Bite-sized (Predation Risk) behaviour of one fish directly conflicts with the Piscivore (Eats small/nano fish) trait of the other — piscivorous fish will prey on nano-sized tank mates..

Additional behavioural considerations to keep in mind: Shrimp eaters may also prey on very small nano fish.

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

The safe temperature window for both species falls between 23°C and 26°C. Aim for the midpoint of this range (around 24.5°C) for optimal comfort.

Both fish can tolerate a pH between 5.5 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 1–10 dGH. Regular testing will ensure conditions stay within this range.

To house Espei Rasbora (Lambchop Rasbora) and One-Spot Betta together, plan for an aquarium of at least 80 litres with a minimum length of 80 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: Plants - Densely covered, Leaf Litter/Blackwater, Plants - Floating, Driftwood (Digestion/Hiding). Meeting these requirements will help both species thrive.

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

Espei Rasbora (Lambchop Rasbora) and One-Spot Betta 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.

Feeding time deserves special attention with this pairing. One-Spot Betta is a known shrimp eater and may prey on small invertebrates or nano fish like Espei Rasbora (Lambchop Rasbora).