Odontesthes bonariensis is a species of Neotropical silverside, an euryhaline fish native to fresh, brackish and salt water in south-central and southeastern South America, but also introduced elsewhere.

[10] Odontesthes bonariensis is native to subtropical and temperate South America east of the Andes where it ranges from around the Río Negro basin in Argentina, north throughout most of the northern half of that country, to the Río de la Plata Basin in south Brazil, Paraguay and Uruguay.

[3][6][8] In coastal Atlantic parts of South America it ranges at least from the southernmost Buenos Aires Province in Argentina to Rio Grande do Sul State (Lagoa dos Patos) in Brazil.

This includes both stagnant and flowing waters, such as rivers, streams, channels, lakes, reservoirs, estuaries and coastal lagoons.

[11][15] Temperatures of 32 °C (90 °F) are lethal to most individuals,[14] and when above 25 °C (77 °F) they often perish due to increases of the parasitic Lernaea copepods (also a primary reason for failed introduction attempts of O. bonariensis in some countries), the bacteria Aeromonas hydrophila and algal blooms.

[7] Overall the species is widespread and common, but global warming can increase the temperature and salinity in some placed inhabited by O. bonariensis, representing a threat to these local populations.

[18] The larvae are unable to survive salinities of 3% (they thrive from 2% to pure fresh water),[19] but they can already live at this relatively high range once they reach the juvenile stage.

It is sometimes kept in aquaculture due to its ability to live in a wide range of environments, the ease of breeding it in captivity and its fast growth.

[11] However, some populations, notably the one in Lake Titicaca, contain levels of metals from pollution that exceed the internationally recommended safety thresholds for human consumption.