Can Marbled Hatchetfish and Mbu Puffer Live Together?

Marbled Hatchetfish is a peaceful species (1/10), while Mbu Puffer is semi-aggressive (7/10). This notable difference means Mbu Puffer may occasionally assert dominance over Marbled Hatchetfish.

Large aggression gap (6 points) between Marbled Hatchetfish and Mbu Puffer increases stress risk for the more peaceful fish.

In terms of spatial distribution, Marbled Hatchetfish prefers the Top (Surface) zone, whereas Mbu Puffer 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.

Additional behavioural considerations to keep in mind: Aggressive fish may bully and stress shy, slow-moving species. Aggressive eaters may outcompete shy fish for food, leading to malnutrition.

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

To improve the chances of a peaceful coexistence in this community tank: A larger aquarium with ample hiding spots can help diffuse aggression and give the less dominant fish space to retreat. Keep fin nippers in larger groups to distribute nipping behaviour among conspecifics rather than tank mates.

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 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 10–12 dGH. Regular testing will ensure conditions stay within this range. An aquarium test kit is recommended for monitoring.

To house Marbled Hatchetfish and Mbu Puffer together, plan for an aquarium of at least 1800 litres with a minimum length of 240 cm. This accounts for the larger species' space requirements with an additional 20 % buffer to reduce territorial tension.

Because this pairing requires extra vigilance, include plenty of hiding spots — caves, driftwood, and dense plant clusters — so the less dominant fish can retreat when needed.

Specific environmental needs for this combination include: Plants - Floating, Leaf Litter/Blackwater, Sand (Sifters), Shells (Breeding/Hiding), Smooth Gravel (Sensitive Barbels). Meeting these requirements will help both species thrive.

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

Feeding time deserves special attention with this pairing. Mbu Puffer is an aggressive eater that may prevent Marbled Hatchetfish from getting enough food.

Because Mbu Puffer is a fast, competitive feeder, consider using sinking pellets or feeding at opposite ends of the setup to ensure Marbled Hatchetfish receives an adequate share.