Can Marbled Hatchetfish and Silver Prochilodus Live Together?

Marbled Hatchetfish is a peaceful species (1/10), while Silver Prochilodus is generally mild-mannered (4/10). This modest difference means Silver Prochilodus may occasionally assert dominance over Marbled Hatchetfish.

In terms of spatial distribution, Marbled Hatchetfish prefers the Top (Surface) zone, whereas Silver Prochilodus 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 Shy / Slow Moving (Easily Stressed) behaviour of one fish directly conflicts with the Slime Coat Eater (Attacks Flat Fish) trait of the other — slime coat eaters target slow-moving fish, causing severe stress and health issues..

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

Worth noting: Marbled Hatchetfish is a known jumper, so a tight-fitting lid is essential.

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.

Both fish can tolerate a pH between 5.5 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 1–12 dGH. Regular testing will ensure conditions stay within this range.

To house Marbled Hatchetfish and Silver Prochilodus together, plan for an aquarium of at least 450 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: Plants - Floating, Leaf Litter/Blackwater, Established Algae (Otocinclus). Meeting these requirements will help both species thrive.

Marbled Hatchetfish prefers Low (Still Water) flow while Silver Prochilodus needs High (River/Stream) flow. Consider positioning filter outlets and using baffles to create zones of different current intensity within the same tank.

Marbled Hatchetfish and Silver Prochilodus 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.