Exodus 7:23 KJV

21And 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.

22And 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.

23And Pharaoh turned and went into his house, neither did he set his heart to this also.

24And all the Egyptians digged round about the river for water to drink; for they could not drink of the water of the river.

25And seven days were fulfilled, after that the LORD had smitten the river.