Can Cardinal Shrimp (Sulawesi) and Wels Catfish (European Catfish) Live Together?

Cardinal Shrimp (Sulawesi) is a peaceful species (0/10), while Wels Catfish (European Catfish) is semi-aggressive (8/10). This notable difference means Wels Catfish (European Catfish) may occasionally assert dominance over Cardinal Shrimp (Sulawesi).

Large aggression gap (8 points) between Cardinal Shrimp (Sulawesi) and Wels Catfish (European Catfish) increases stress risk for the more peaceful fish.

Cardinal Shrimp (Sulawesi) and Wels Catfish (European Catfish) 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 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: Aggressive fish may bully and stress shy, slow-moving species.

Worth noting: Wels Catfish (European Catfish) is nocturnal and will be most active after lights-out, naturally reducing daytime encounters.

There is no temperature overlap between Cardinal Shrimp (Sulawesi) (26–30°C) and Wels Catfish (European Catfish) (4–25°C). This fundamental mismatch makes long-term cohabitation impractical.

Both fish can tolerate a pH between 7.5 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 5–8 dGH. Regular testing will ensure conditions stay within this range.

To house Cardinal Shrimp (Sulawesi) and Wels Catfish (European Catfish) together, plan for an aquarium of at least 10000 litres with a minimum length of 400 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: Established Algae (Otocinclus), Smooth Gravel (Sensitive Barbels), Sand (Sifters), 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.

Cardinal Shrimp (Sulawesi) and Wels Catfish (European Catfish) 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.