Can Cigar Shark (Mad Barb) and Copper Harlequin Rasbora Live Together?

Cigar Shark (Mad Barb) is a generally mild-mannered species (4/10), while Copper Harlequin Rasbora is peaceful (1/10). This modest difference means Cigar Shark (Mad Barb) may occasionally assert dominance over Copper Harlequin Rasbora.

Cigar Shark (Mad Barb) and Copper Harlequin Rasbora 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 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: Hyperactive swimmers can stress shy, slow-moving species through constant motion. Aggressive eaters may outcompete shy fish for food, leading to malnutrition.

Worth noting: Cigar Shark (Mad Barb) is a known jumper, so a tight-fitting lid is essential.

The safe temperature window for both species falls between 23°C and 28°C. Aim for the midpoint of this range (around 25.5°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 4–10 dGH. Regular testing will ensure conditions stay within this range.

To house Cigar Shark (Mad Barb) and Copper Harlequin Rasbora together, plan for an aquarium of at least 1000 litres with a minimum length of 240 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: Smooth Gravel (Sensitive Barbels), Plants - Densely covered, Plants - Floating, Leaf Litter/Blackwater. Meeting these requirements will help both species thrive.

Note a potential conflict in setup requirements: Cigar Shark (Mad Barb) is a plant destroyer, which conflicts with Copper Harlequin Rasbora's requirement for live plants. Compromise where possible or prioritise the more critical need.

Both species do well with high (river/stream) water movement, so a standard filtration setup rated for the tank volume should suffice.

Cigar Shark (Mad Barb) and Copper Harlequin 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. Cigar Shark (Mad Barb) is an aggressive eater that may prevent Copper Harlequin Rasbora from getting enough food.

Because Cigar Shark (Mad Barb) is a fast, competitive feeder, consider using sinking pellets or feeding at opposite ends of the setup to ensure Copper Harlequin Rasbora receives an adequate share.