Marbled hatchetfish

Behaviour and habits

The marbled hatchetfish is a small, peaceful, surface-dwelling fish with a deep, hatchet-shaped belly and a habit of hovering just under the surface, hunting for food that drifts or falls. It is a shoaler that does best in a group of six or more in soft, warm, dimly lit water, and it is a genuine jumper with a powerful leap, so a tight lid is essential. Its unusual shape and surface behaviour make it a rewarding specialist for a planted tank.

What to feed, and how often

A micro-predator that takes small foods from the surface — fruit flies, small daphnia, baby brineshrimp and tiny floating foods. Feed one or two small meals a day, and make sure it is not out-competed by mid-water fish, as it feeds almost exclusively at the surface.

Water changes and maintenance

Change about 20–25% weekly in soft, warm water, matched closely. It dislikes hard water and sudden changes, and it does best in a mature, stable, dimly lit planted tank.

Care and how easy it is

A specialist surface fish for a soft-water, planted tank with a tight lid and calm, non-bullying tankmates.

Common health problems

Sensitive to poor water; can suffer bacterial and fungal problems when stressed.

If it gets sick

Keep the water soft, warm and very stable, feed at the surface, and isolate and treat early if an infection shows.