Kneri Prochilodus/Flagtail Semaprochilodus kneri

The Flagtail Characins, genus Semaprochilodus, are some half a dozen similar-looking silver freshwater shoaling fish native to South America, from the Amazon, Orinoco and Maroni basins. Most have orange or yellow fins and tails with various degrees of black stripes. All were previously in genus Prochilodus and retain that as one of their common names.

The Kneri Flagtail is sometimes called the Flagtail Prochilodus, which isn't helpful since all others in the genus are also called Flagtails. It is native to the Orinoco Basin and can grow to 28cm long.