The golden dorado is known to science as Salminus maxillosus, and to romantics as “the tiger of the Amazon.” It sits at the very pinnacle of its food chain. The largest recorded example weighed in at 68 pounds of raw, carniverous power, and it seems likely that they come a good deal larger than that. Typical sizes on the Tarija are in the 6- to 25-pound range, with the ever-present possibility of something that will rip your arms from their sockets.
Dorado have enormous heads, and their powerful jaws are full of gleaming,razor-like teeth. They generally move in small groups, chewing their way through a catholic variety of prey—fish and frogs, birds and mammals. In the Tarija, the dorado are particularly fond of sabalo, a schooling fish of two to six pounds, which a dorado can swallow in a single gulp. The presence of sabalo, detectable from the surface bubbles that they create, is an almost certain indication that dorado are nearby.
In spite of the Salminus in its scientific name, the dorado is unrelated to the salmonids—nor is it related to the saltwater fish also called “dorado.” It lives in the warm waters of the Plata and Amazon systems, in Brazil, Argentina, Paraguay,Uruguay, and Bolivia. In the slower-moving lowland streams and marshes, closer to population centers, the species has been a regular quarry for anglers for many years, and it is well known for the excitement it provides. But only a few pioneers have so far pursued it with the fly in the less accessible, but spectacularly beautiful,upper reaches of its range.