👉 Rivulinae is a genus of fish in the family Cyprinidae, commonly known as carp or rainbow trout. They are native to North America and are characterized by their unique body shape, with a streamlined appearance that allows them to swim swiftly through water currents. RIVULINAE, meaning "riverine" or "rivuletine," is used to denote the genus of aquatic animals found in bodies of water where there is frequent flow of water and fish migration.