Exodus 7:20-25King James Version (KJV)
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.
21 And the fish that was in the river died; and the river stank, and the Egyptians could not drink of the water of the river; and there was blood throughout all the land of Egypt.
22 And the magicians of Egypt did so with their enchantments: and Pharaoh's heart was hardened, neither did he hearken unto them; as the Lord had said.
23 And Pharaoh turned and went into his house, neither did he set his heart to this also.
24 And all the Egyptians digged round about the river for water to drink; for they could not drink of the water of the river.
25 And seven days were fulfilled, after that the Lord had smitten the river.