Triportheus is a genus of freshwater ray-finned fishes belonging to the family Triportheidae, the hatchet characins or keeled characins. The fishes in this genus are found in South America, including Trinidad, ranging from the Rio de la Plata basin to the basins of the Orinoco and Magdalena. Some are migratory. This genus is classified in the subfamily Triportheinae.

The largest species is up to 36 cm (14 in) in standard length, but most reach up to about 2⁄3 of that size or less. They somewhat resemble larger, more elongated hatchetfish, including a keeled chest and large pectoral fins. This leads to the common names narrow hatchetfish and elongate hatchetfish, the latter also used more specifically for T. elongatus. Their shape is an adaption for living near the water surface where they find most of their food such as fruits, seeds, leaves, flowers, other plant material, invertebrates (insects, spiders and alike) and occasionally small fish. Seeds eaten by Triportheus are sometimes crushed, but may also pass undamaged through the fish, making them potential seed dispersers.

...