Exodus 7:24

The fish that were in the river died. The river became foul. The Egyptians couldn’t drink water from the river. The blood was throughout all the land of Egypt.

The magicians of Egypt did the same thing with their enchantments. So Pharaoh’s heart was hardened, and he didn’t listen to them, as the LORD had spoken.

Pharaoh turned and went into his house, and he didn’t even take this to heart.

Seven days were fulfilled, after the LORD had struck the river.