Can Banded Archerfish (Brackish) and Otocinclus Live Together?

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

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

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

There is a critical concern: the Piscivore (Eats small/nano fish) behaviour of one fish directly conflicts with the Nano / Bite-sized (Predation Risk) trait of the other — piscivorous fish will prey on nano-sized tank mates..

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

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. An aquarium test kit is recommended for monitoring.

To house Banded Archerfish (Brackish) and Otocinclus together, plan for an aquarium of at least 360 litres with a minimum length of 120 cm. This accounts for the larger species' space requirements with an additional 20 % buffer to reduce territorial tension.

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), Established Algae (Otocinclus), Plants - Densely covered, Smooth Gravel (Sensitive Barbels). 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.