Can Ceylon Puffer (Brackish) and Chocolate Gourami Live Together?

Ceylon Puffer (Brackish) is a semi-aggressive species (8/10), while Chocolate Gourami is peaceful (2/10). This notable difference means Ceylon Puffer (Brackish) may occasionally assert dominance over Chocolate Gourami.

Large aggression gap (6 points) between Ceylon Puffer (Brackish) and Chocolate Gourami increases stress risk for the more peaceful fish.

Ceylon Puffer (Brackish) and Chocolate Gourami 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.

The safe temperature window for both species falls between 25°C and 28°C. Aim for the midpoint of this range (around 26.5°C) for optimal comfort.

The pH requirements of Ceylon Puffer (Brackish) (7.5–8.5) and Chocolate Gourami (4–6.5) do not overlap, making it impossible to satisfy both species simultaneously.

Hardness requirements are incompatible: Ceylon Puffer (Brackish) needs 12–30 dGH while Chocolate Gourami requires 0–5 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 Ceylon Puffer (Brackish) and Chocolate Gourami together, plan for an aquarium of at least 150 litres with a minimum length of 90 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: Shells (Breeding/Hiding), Sand (Sifters), Leaf Litter/Blackwater, Plants - Densely covered, Plants - Floating, Driftwood (Digestion/Hiding). Meeting these requirements will help both species thrive.

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

Ceylon Puffer (Brackish) and Chocolate Gourami 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.