FILE - In this Jan. 12, 2010 file photo, Asian bighead carp swim in an exhibit at Chicago's Shedd Aquarium. Members of Congress proposed legislation Thursday, Feb. 26, 2015, calling for additional obstacles to prevent Asian carp from reaching Lake Michigan through an Illinois waterway and a renewed push toward a permanent strategy for shielding the Great Lakes from the destructive fish. (AP Photo/M. Spencer Green, File)