The aquarium fish trade is characterized by an enormous number of species. Aquarium fish may have an impact on native biota by means of their invasiveness as well as through pathogen transfer. The Czech Republic has become a gateway for aquatic pets into the European Union. The aims of this study were to identify the most common aquarium fish species on the wholesale market, to estimate temperature suitability for seasonal (winter and summer) survival in the EU, and also to assess the invasiveness risk of the most common aquarium fishes with the strongest temperature matching.