Zu elongatus, or the taper-tail ribbonfish, is a species of ray-finned fish within the family Trachipteridae.

[1] The species distribution is poorly known, and while it likely lives in temperate and tropical waters of all oceans, but has only been encountered in the Atlantic Ocean- off the coasts of Namibia and the western Cape of South Africa- and in the Pacific Ocean off New Zealand.

[2] Zu elongatus grows to a length of 120 centimeters and has a silvery grey coloration with bars along the sides.

Juveniles are epipelagic, spending time near the surface, and have trailing, elongated dorsal and pelvic fins that mimic siphonophores and jellyfish.

Eggs of Zu elongatus are large and free floating with a bright red coloration.