Can Mono Sebae (Brackish) and Neon Green Rasbora (Kubotai) Live Together?

Mono Sebae (Brackish) is a generally mild-mannered species (4/10), while Neon Green Rasbora (Kubotai) is peaceful (1/10). This modest difference means Mono Sebae (Brackish) may occasionally assert dominance over Neon Green Rasbora (Kubotai).

Mono Sebae (Brackish) and Neon Green Rasbora (Kubotai) 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: Shrimp eaters may also prey on very small nano fish.

Worth noting: Neon Green Rasbora (Kubotai) is a known jumper, so a tight-fitting lid is essential.

The safe temperature window for both species falls between 24°C and 27°C. Aim for the midpoint of this range (around 25.5°C) for optimal comfort.

Both fish can tolerate a pH between 7.5 and 7.5. Maintaining a stable value within this band is more important than hitting an exact number.

Hardness requirements are incompatible: Mono Sebae (Brackish) needs 12–30 dGH while Neon Green Rasbora (Kubotai) requires 2–10 dGH.

Crucially, these species require different water types — one needs freshwater while the other requires brackish conditions. This is a hard barrier to keeping them together.

To house Mono Sebae (Brackish) and Neon Green Rasbora (Kubotai) together, plan for an aquarium of at least 400 litres with a minimum length of 150 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), Smooth Gravel (Sensitive Barbels), Plants - Densely covered, Plants - lighly covered, Leaf Litter/Blackwater. Meeting these requirements will help both species thrive.

Note a potential conflict in setup requirements: Mono Sebae (Brackish) is a plant destroyer, which conflicts with Neon Green Rasbora (Kubotai)'s requirement for live plants. Compromise where possible or prioritise the more critical need.

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

Mono Sebae (Brackish) and Neon Green Rasbora (Kubotai) 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. Mono Sebae (Brackish) is a known shrimp eater and may prey on small invertebrates or nano fish like Neon Green Rasbora (Kubotai).

Because Mono Sebae (Brackish) is a fast, competitive feeder, consider using sinking pellets or feeding at opposite ends of the setup to ensure Neon Green Rasbora (Kubotai) receives an adequate share.