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

Green Neon Tetra is a peaceful species (0/10), while Mono Sebae (Brackish) is generally mild-mannered (4/10). This notable difference means Mono Sebae (Brackish) may occasionally assert dominance over Green Neon Tetra.

Green Neon Tetra and Mono Sebae (Brackish) 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. Aggressive eaters may outcompete shy fish for food, leading to malnutrition. Shrimp eaters may also prey on very small nano fish.

The safe temperature window for both species falls between 24°C and 28°C. Aim for the midpoint of this range (around 26.0°C) for optimal comfort.

The pH requirements of Green Neon Tetra (4.5–6.5) and Mono Sebae (Brackish) (7.5–8.5) do not overlap, making it impossible to satisfy both species simultaneously.

Hardness requirements are incompatible: Green Neon Tetra needs 1–8 dGH while Mono Sebae (Brackish) requires 12–30 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 Green Neon Tetra and Mono Sebae (Brackish) 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: Leaf Litter/Blackwater, Plants - Densely covered, Plants - Floating, Sand (Sifters), Smooth Gravel (Sensitive Barbels). 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 Green Neon Tetra's requirement for live plants. Compromise where possible or prioritise the more critical need.

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

Green Neon Tetra and Mono Sebae (Brackish) 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 Green Neon Tetra. Mono Sebae (Brackish) is an aggressive eater that may prevent Green Neon Tetra from getting enough food.

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