It has largely been converted to agriculture or occupied by urban development, but scattered patches of the original habitat remain along the river.

Mammals include agile gracile opossum (Gracilinanus agilis), coypu (Myocastor coypus) and Argentine swamp rat (Scapteromys aquaticus).

[2] Rare, endemic or endangered species include polka-dot tree frog (Hypsiboas punctatus), marsh deer (Blastocerus dichotomus), neotropical otter (Lontra longicaudis) and capybara (Hydrochoerus hydrochaeris).

[2] Endangered amphibians include blunt-headed salamander (Ambystoma amblycephalum) and red-spotted Argentina frog (Argenteohyla siemersi).

[5] Birds include biguá (Phalacrocórax olivaceus), rufescent tiger heron (Tigrisoma lineatum), striped owl (Pseudoscops clamator), green kingfisher (Chloroceryle americana), great black hawk (Buteogallus urubitinga), roadside hawk (Rupornis magnirostris), dusky-legged guan (Penelope obscura), checkered woodpecker (Veniliornis mixtus), greater thornbird (Phacellodomus ruber), rufous-bellied thrush (Turdus rufiventris) and straight-billed reedhaunter (Limnoctites rectirostris).

[2] Endangered birds include yellow cardinal (Gubernatrix cristata), Chaco eagle (Buteogallus coronatus) and Eskimo curlew (Numenius borealis).

Species of fish that attract tourists for sports fishing include spotted sorubim (Pseudoplatystoma corruscans), barred sorubim (Pseudoplatystoma fasciatum), paulicea Amazon catfish (Paulicea lutkeni), dorado (Salminus brasiliensis) and pirapitá (Brycon orbiginianus).