Can Asian Upside Down Catfish and Espei Rasbora (Lambchop Rasbora) Live Together?

Asian Upside Down Catfish is a semi-aggressive species (8/10), while Espei Rasbora (Lambchop Rasbora) is peaceful (1/10). This notable difference means Asian Upside Down Catfish may occasionally assert dominance over Espei Rasbora (Lambchop Rasbora).

Large aggression gap (7 points) between Asian Upside Down Catfish and Espei Rasbora (Lambchop Rasbora) increases stress risk for the more peaceful fish.

Asian Upside Down Catfish and Espei Rasbora (Lambchop Rasbora) both frequent the Middle (Open Water) 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 Piscivore (Eats small/nano fish) behaviour of one fish directly conflicts with the Nano / Bite-sized (Predation Risk) 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: Asian Upside Down Catfish is nocturnal and will be most active after lights-out, naturally reducing daytime encounters.

The safe temperature window for both species falls between 23°C and 27°C. Aim for the midpoint of this range (around 25.0°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 5–12 dGH. Regular testing will ensure conditions stay within this range.

To house Asian Upside Down Catfish and Espei Rasbora (Lambchop Rasbora) together, plan for an aquarium of at least 380 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: Driftwood (Digestion/Hiding), Smooth Gravel (Sensitive Barbels), Plants - Densely covered, Leaf Litter/Blackwater. 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.

Asian Upside Down Catfish and Espei Rasbora (Lambchop Rasbora) 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. Asian Upside Down Catfish is a known shrimp eater and may prey on small invertebrates or nano fish like Espei Rasbora (Lambchop Rasbora).