Phil Willink from Chicago's Field Museum holds a northern snakehead fish from China during a press conference at Chicago's Burnham Harbor, Tuesday, Oct. 19, 2004. Biologists set large nets into the harbor Monday in search of a snakehead, like the one shown, after one of the species was caught in the harbor last week. The northern snakehead, so-called "Frankenfish," is a type of fish known for its voracious appetite and ability to wreak havoc on freshwater ecosystems. No snakeheads were found in the nets, bolstering a theory that the snakehead caught was simply dumped out of an aquarium by someone who didn't know what else to do with it. (AP Photo/Nam Y. Huh)