Commentaries:
The Egyptians held the Nile River to be sacred, as they did with many of its fish and the crocodiles that lined its banks. God punctured this belief when He turned the river waters to blood, making it unfit to drink or use. Millions of fish died and stank, as did probably thousands of crocodiles.
Mike Ford
Animal Idolatry
Other Forerunner Commentary entries containing Exodus 7:14:
Exodus 4:21
Amos 4:6-11
John 2:1-11
Revelation 11:6