Rio Ubatiba, also known as Rio Silvado, is a low-elevation second-order stream nestled within the Serra do Mar mountain range in the state of Rio de Janeiro, Brazil. Flowing through meadows that have been partially deforested for agricultural use, this Atlantic Forest stream is a fascinating destination for anglers interested in exploring the rich native fish diversity of southeastern Brazil's coastal drainages. The river sits within the Lagos bioregion — one of the smaller drainage systems in the state — which encompasses the coastal wetlands and lagoon systems of the Maricá and Saquarema region. Despite its modest size, Rio Ubatiba supports a surprisingly diverse community of native stream fish, making it a rewarding destination for those willing to explore its waters with light tackle and a naturalist's curiosity.