Can Banded Archerfish (Brackish) and Julii Corydoras (False Julii) Live Together?

Banded Archerfish (Brackish) is a moderately assertive species (6/10), while Julii Corydoras (False Julii) is peaceful (0/10). This notable difference means Banded Archerfish (Brackish) may occasionally assert dominance over Julii Corydoras (False Julii).

Large aggression gap (6 points) between Banded Archerfish (Brackish) and Julii Corydoras (False Julii) increases stress risk for the more peaceful fish.

In terms of spatial distribution, Banded Archerfish (Brackish) prefers the Top (Surface) zone, whereas Julii Corydoras (False Julii) occupies the Bottom (Substrate) zone. Because they use different levels of the water column, territorial disputes are less likely and the tank will appear more balanced.

Worth noting: Banded Archerfish (Brackish) is a known jumper, so a tight-fitting lid is essential.

The safe temperature window for both species falls between 24°C and 26°C. Aim for the midpoint of this range (around 25.0°C) for optimal comfort.

Both fish can tolerate a pH between 7 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 15–15 dGH. Regular testing will ensure conditions stay within this range.

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 Banded Archerfish (Brackish) and Julii Corydoras (False Julii) together, plan for an aquarium of at least 300 litres with a minimum length of 120 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), 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.

Banded Archerfish (Brackish) and Julii Corydoras (False Julii) 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.