This family of fish is closely related to the Gharacidae and belongs to the super-order Os-tariophysi, sub-order Gharacoidei and is grouped under the family Gasteropelecidae which represents the hatchet fish, or flying Gharacins. These fish are known as hatchet fish because they have a body shape resembling the blade of an axe, or hatchet-very slim, when viewed from the front, and very deep when viewed from the side.
There are three genera in the family, and in all three the species have well developed pectoral fins, not unlike wings, which are used by the fish to skim the water surface, and even to become airborne.