Moses
Exodus 7:18BSB·traditional attribution

The fish in the Nile will die, the river will stink, and the Egyptians will be unable to drink its water.’”

Matthew Henry Presbyterian @wholebiblehenry

Here is the first of the ten plagues, the turning of the water into blood, which was, 1. A dreadful plague, and very grievous. The very sight of such vast rolling streams of blood, pure blood no doubt, florid and high-colored, could not but strike a horror upon people: much more afflictive were the consequences of it.

Commenting on Exodus 7:14-25

John Gill Reformed Baptist @doctorgill

And the fish that is in the river shall die,.... Their element being changed, and they not able to live in any other but water: and the river shall stink; with the blood, into which it should be congealed, and with the putrefied bodies of fishes floating in it: and the Egyptians shall loath to drink of the water of the river; the very colour...

Adam Clarke Methodist @methodicalclarke

The Egyptians shall loathe to drink of the water - The force of this expression cannot be well felt without taking into consideration the peculiar pleasantness and great salubrity of the waters of the Nile. "The water of Egypt," says the Abbe Mascrier, "is so delicious, that one would not wish the heat to be less, or to be delivered from the sensation of thirst.