Can Discus and Smallmouth Bass Live Together?

Discus is a generally mild-mannered species (4/10), while Smallmouth Bass is semi-aggressive (7/10). This modest difference means Smallmouth Bass may occasionally assert dominance over Discus.

Discus and Smallmouth Bass both frequent the Middle (Open Water) and 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.

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. Aggressive eaters may outcompete shy fish for food, leading to malnutrition. Two territorial species may clash over territory, especially in smaller tanks.

Worth noting: Smallmouth Bass is a known jumper, so a tight-fitting lid is essential.

There is no temperature overlap between Discus (28–32°C) and Smallmouth Bass (15–25°C). This fundamental mismatch makes long-term cohabitation impractical.

Both fish can tolerate a pH between 6.5 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 5–12 dGH. Regular testing will ensure conditions stay within this range.

To house Discus and Smallmouth Bass together, plan for an aquarium of at least 680 litres with a minimum length of 180 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: Sand (Sifters), Driftwood (Digestion/Hiding), Leaf Litter/Blackwater, Smooth Gravel (Sensitive Barbels). Meeting these requirements will help both species thrive.

Discus prefers Low (Still Water) flow while Smallmouth Bass needs High (River/Stream) flow. Consider positioning filter outlets and using baffles to create zones of different current intensity within the same tank.

Discus and Smallmouth Bass 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. Smallmouth Bass is an aggressive eater that may prevent Discus from getting enough food.

Because Smallmouth Bass is a fast, competitive feeder, consider using sinking pellets or feeding at opposite ends of the setup to ensure Discus receives an adequate share.