Occurs in ponds (Ref. 11229). Inhabits shallow, densely vegetated microhabitats in small streams or along the banks of larger rivers (Ref. 106564). Feeds mostly on fishes (Ref. 598). Two rodents (Sigmodontinae) were found in the stomachs of two individuals in different rivers located in the southern Brazilian Atlantic Rain Forest, in March and November 2010. These represent the first records of this species feeding on mammals (Ref. 106564).
Alexandre C. Ribeiro, 2007, Oligosarcus perdido (Characiformes, Characidae), a new species of freshwater fish from Serra da Bodoquena, upper Rio Paraguai basin, Brazil., Zootaxa, pp. 43-53, vol. 1560