Asian carp have invaded the Mississippi River, and destroyed its lucrative fishing industry. Today, only an electric fence is keeping them from entering the Great Lakes, and a few have already been spotted. If any more cross that barrier, prepare for Carpageddon. The Water Brothers find out what an Asian carp invasion could do to the Great Lakes’ 7 billion dollar fishing economy and examine how other invasive species like zebra mussels have changed the Great Lakes ecosystem.