Any colour you like: new records of ornamental livebearers (Poeciliidae: Cyprinodontiformes) from freshwaters of Argentina. Author Terán, Guillermo E. Fundación Miguel Lillo, Unidad Ejecutora Lillo (CONICET-FML), Miguel Lillo 251, 4000 San Miguel de Tucumán guilloteran@gmail.com Author Koerber, Stefan Independent researcher. Friesenstr. 11, 45476 Muelheim, Germany. pecescriollos @ koerber-germany. de pecescriollos@koerber-germany.de Author Stazzonelli, Juan Carlos Fundación Miguel Lillo, Miguel Lillo 251, 4000 San Miguel de Tucumán, Argentina Author Aguilera, Gastón Fundación Miguel Lillo, Unidad Ejecutora Lillo (CONICET-FML), Miguel Lillo 251, 4000 San Miguel de Tucumán Author Mirande, J. Marcos Fundación Miguel Lillo, Unidad Ejecutora Lillo (CONICET-FML), Miguel Lillo 251, 4000 San Miguel de Tucumán text Ichthyological Contributions of PecesCriollos 2022 2022-03-15 80 1 8 journal article 298606 10.5281/zenodo.11558417 d37631a4-f113-42bf-abd6-10f034777748 1868-3703 11558417 Poecilia reticulata and Xiphophorus hellerii – widely introduced around the globe Among the family Poeciliidae , Poecilia Bloch & Schneider, 1801 , is the most diverse genus represented by 75 species ( Huber 2019 ; Fricke et al. 2022 ), from which the guppy, Poecilia reticulata Peters, 1859 , is one of the most popular aquarium fish in the world ( fig. 22 ; Lucinda & Van der Sleen 2018 ). This species is native from Northeastern South America and Trinidad and Tobago , with the type locality in the Guayre River in Venezuela . The native range of this species includes Brazil , Guyana , Surinam ( fig. 21 ), Venezuela , and Trinidad and Tobago (Rosen & Bayley 1963; Bragança et al. 2020 ). Currently, its presence in natural environments is known to occur in almost 70 countries outside of the species’ native range ( Deacon et al. 2011 ). Non-native populations are known from Asia, Africa, Australasia-Pacific, Europe, North America, and South America ( GBIF 2016). In South America, Poecilia reticulata has been recorded mostly in the northern region of the continent. The presence of this invasive species was confirmed from Paraguay ( Lucinda 2017 ) and Argentina ( Rosso et al. 2017 ), both records from the Paraguay River basin. The capacity of guppies to form large populations within the environment to which it was introduced could produce an increasing in competition with native fishes for food resources and changing rates of nutrient and/or organic-matter cycling ( López-Fuentes et al. 2021 ). Species of the genus Xiphophorus are native from Belize , Guatemala , Honduras , and especially Mexico . Nevertheless, two species of platies, X. maculatus (Günther, 1866) and X. variegatus (Meek, 1904) , and the swordtail X. hellerii Heckel, 1848 , have been introduced globally in many different countries and environments. Xiphophorus hellerii today is found as an introduced non-native species in self-substaining populations in over 30 countries, sometimes from multiple introductions in different places as e.g. in several distinct states of Australia or the US ( Maddern et al. 2011 ; Nico et al. 2021 ). Most of these introductions have happened in areas with tropical or subtropical climate. Yet, the species is also found in colder areas where is has been introduced in thermal waters, as e.g. in Hungary ( Pandakov et al. 2021 ), where it could surely not survive the harsh winters in natural ’unheated‘ water bodies which may even feature a frozen surface during winter. In the present contribution we report for the first time the presence of Xiphophorus hellerii for Argentina and of Poecilia reticulata from Tucumán , Argentina .