Often when some fish are stressed a few who are able to continue functioning will feast on the stressed. Good example - we rotenoned part of a lake and the non stressed fish from the other end of the lake moved to the transition zone ( where clean water met rotenone) and dined on the dying fish. Got out a rod and caught 9 big LMB ( 5-7 lbs) on 11 casts using an injured shad lure .