Fish should be understood as plural and generic, referring to all the different kinds of fresh water fish and living creatures in the Nile River. They shall die because the water of the river will be changed into blood. The Nile shall become foul means that “the river will stink” (Good News Translation), for the word foul refers to a bad odor, not to pollution (as in New American Bible). The same word is used of the dead frogs in 8.14 and of the spoiled manna in 16.20. The bad odor of the Nile was evidently the result of the dead fish rather than the blood. (See also verse 21 below.)

It is not clear from the text just why the Egyptians would loathe to drink the water from the Nile. Obviously, the blood and the dead fish would make the water “polluted” (New American Bible), but it is possible that they would loathe to drink because of the smell. The English word loathe carries the meaning “will not want to drink” (Jerusalem Bible), but the Hebrew word means “to become tired” and suggests that “the Egyptians will look in vain in the Nile for water fit to drink” (Translator’s Old Testament). In context, however, the meaning seems clear: “the Egyptians will not be able to drink from it” (Good News Translation).

Quoted with permission from Osborn, Noel D. and Hatton, Howard A. A Handbook on Exodus. (UBS Helps for Translators). New York: UBS, 1999. For this and other handbooks for translators see here .