Exodus 7:19-25
English Standard Version
20Moses and Aaron did as the Lord commanded. In the sight of Pharaoh and in the sight of his servants he lifted up the staff and struck the water in the Nile, and all the water in the Nile turned into blood.
21And the fish in the Nile died, and the Nile stank, so that the Egyptians could not drink water from the Nile. There was blood throughout all the land of Egypt.
22But the magicians of Egypt did the same by their secret arts. So Pharaoh 's heart remained hardened, and he would not listen to them, as the Lord had said.
23Pharaoh turned and went into his house, and he did not take even this to heart.
24And all the Egyptians dug along the Nile for water to drink, for they could not drink the water of the Nile.