Exodus 7:17 Thus saith the LORD, In this thou shalt know that I am the LORD: behold, I will smite with the rod that is in mine hand upon the waters which are in the river, and they shall be turned to blood.

Exodus 7:20 And Moses and Aaron did so, as the LORD commanded; and he lifted up the rod, and smote the waters that were in the river, in the sight of Pharaoh, and in the sight of his servants; and all the waters that were in the river were turned to blood.

Psalms 105:29 He turned their waters into blood, and slew their fish.