Hyphessobrycon agulha

Hyphessobrycon agulha, also called the red-tailed flag tetra, is a species of freshwater ray-finned fish belonging to the family Acestrorhamphidae, the American characins.^[2] This fish is found in the basin of the Madeira River in Brazil along with parts of Peru and Bolivia. It reaches a maximum length of 4.3 centimetres (1.7 in).^[3] Though it is mainly found in the wild, it is occasionally kept by fishkeepers^[4] and is sometimes confused with the neon tetra.^[5] The fish is primarily an insectivore, though it does eat vegetable matter.^[6] It is considered to form a group with other species in Hyphessobrycon as they share a dark stripe running lengthwise.^[7]

While its name comes from the native name for this species along the Madeira River in Brazil,^[8] the fish also occurs in Colombia and Peru.