Can Betta Macrostoma and Iridescent Shark Live Together?

Betta Macrostoma is a moderately assertive species (6/10), while Iridescent Shark is generally mild-mannered (3/10). This modest difference means Betta Macrostoma may occasionally assert dominance over Iridescent Shark.

Betta Macrostoma and Iridescent Shark 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.

Additional behavioural considerations to keep in mind: Hyperactive swimmers can stress shy, slow-moving species through constant motion.

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

The safe temperature window for both species falls between 22°C and 25°C. Aim for the midpoint of this range (around 23.5°C) for optimal comfort.

The pH requirements of Betta Macrostoma (4–6) and Iridescent Shark (6.5–7.5) do not overlap, making it impossible to satisfy both species simultaneously.

For general hardness, the shared comfort zone is 2–5 dGH. Regular testing will ensure conditions stay within this range.

To house Betta Macrostoma and Iridescent Shark together, plan for an aquarium of at least 2000 litres with a minimum length of 250 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: Leaf Litter/Blackwater, Driftwood (Digestion/Hiding), Plants - Floating, Smooth Gravel (Sensitive Barbels). 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.