Aquarium Buddies: Hatchet Fish

Hatchet fish (A.K.A. common hatchetfish, silver hatchet fish, and river hatchet fish) are freshwater fish that have a tendency to be timid and peaceful thus making them perfect for aquariums. The origin of its name comes from its unique hatchet-like shape. The body is much larger near the mouth and becomes increasingly smaller near the caudal fin. For aquarium owners, their most interesting feature is that they can jump or fly out of the water, which is aided by pectoral fins. Because of this, aquariums should be closed off but still have enough room for this activity.

Found in South America, hatchet fish grow to about two and a half inches long and spend their time swimming at the surface of the aquarium, or river if they're wild. Both their mouth and eyes point towards the surface, making the fish adapt to eating off the surface. Being carnivores, vinegar flies, brine shrimp, and blood worms make the perfect meal, although, they will eat flake food. Also note because of their autonomy, hatchet fish will typically only eat at the surface and they need to be provided a healthy dose of protein. Aquariums should be set at 26-28 degrees Celsius with a pH of 6.0 to 7.0 to accommodate this type of fish. They are also susceptible to Ich and it is recommended to place them into a quarantined tank.

Other Species of Hatchet Fish

Marble hatchet fish are also freshwater fish. Its name comes from its marble color and the gold line that goes from its eye to its caudal fin. They are very much the same as the silver hatchet fish except for its smaller size, color, and slight preference to cooler temperatures. These fish are school fish and like to travel together in packs. As such they should be bought in groups in order to live more instinctually, plus it's just cool to watch.

Marine hatchet fish are the deep water equivalent to common hatchetfish and won't survive in an aquarium and are provided here for informational purposes. These fish grow quiet large, six inches (fifteen centimeters), and swim down to depths of 3,600 meters. They have larger, more tubular eyes than its freshwater counterpart in order to see the trace light at the depth of water it lives but otherwise its autonomy is the same. Also, they swim nearer to the surface to eat at night and have the ability of produce its own light in order to avoid predators.