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. It is often known by the common name Argentinian silverside or pejerrey, but it is not the only species of silverside in Argentina and pejerrey is also used for many other silversides. It is a commercially important species and the target of major fisheries.

Lake Titicaca is a large freshwater lake in the Andes mountains on the border of Bolivia and Peru. It is often called the highest navigable lake in the world. Titicaca is the largest lake in South America both in terms of the volume of water and surface area.