Thousands Of Dead Fish In The Red River -Locals Suspect Some Sort Of Chemical Spill. Love County, Oklahoma -- Fishermen in a small community in southern Oklahoma are looking for answers after finding thousands of dead fish on the Red River. The Red River is a major tributary of the Mississippi and Atchafalaya rivers in the southern United States of America. The river gains its name from the red-bed country of its watershed. The Red River is the second largest river basin in the southern Great Plains.