This species is native to South America and can be found throughout the Laguna de Araruama basin and Das Ostras River basin as well the coastal plains and mouth region of the Sao Joao River in Brazil. These fish are an annual species and thus tend to inhabit bodies of temporary water such as pools and streams in floodplains as well as lagoons. Rio Pearlfish are typically dark brown in color and exhibit a number of tiny light blue dots all over their bodies and fins. In some specimens these dots coalesce to form lines along the body. The dorsal and anal fins of this species are often pointed and may exhibit bands of reddish brown and yellow in addition to several light blue spots.