The Rivulidae are a family of killifishes in the order Cyprinodontiformes. They are commonly known as rivulids, South American killifish or New World killifish. The latter names are slightly misleading, however, as they are neither restricted to South America – though most are in fact found there –, nor are they the only killifishes from the Americas. Occasionally, they are still referred to as rivulines, a term dating back to when they were considered a subfamily of the Aplocheilidae.