The number of exotic freshwater ornamental fish species released from the aquarium trade in Iran has been increasing in recent years. All recorded exotic aquarium fishes are listed here, including 8 species in 7 genera, 5 families, and 5 orders. The introduced species belong to the Neotropical, Nearctic and Palearctic fish elements. Their distribution ranges within Iranian freshwater ecosystems are given, and the presence of Koi (ornamental Cyprinus carpio) are recorded for the first time from Iranian inland waters. Eradication programs need to be accompanied by a public awareness campaign to ensure that the aquarium trade and hobbyists do not release these pet fishes into natural habitats.