On the fifth day were created the denizens of the water and the atmosphere; the creatures that move in swarms in the water, all winged creatures, including insects, and the sea monsters, especially, perhaps, such as belong to mythology, and fishes. The rendering bring forth abundantly is inaccurate; the margin gives the sense, though it would be better to translate with Driver. Let the waters swarm with swarming things (even) living souls. The term is used of creatures that move in swarms whether in the water (as here) or out of it. The RV often renders it creeping things (similarly the verb), which is the proper rendering of a noun (remes) Genesis 1:24, the verb of which is translated moveth in Genesis 1:21. On the distinction see Driver's article, Creeping Things, in HDB. The rendering creature that hath life is more tolerable to the English ear than living souls, but it conceals the interesting fact that the term souls could be used of the lower creation as well as of men. There is no necessity to infer that the author regarded the winged creatures as derived from the water. The fact that they fly in front of the firmament, i.e. skim the surface of the sky turned towards the earth, shows that the writer regarded it as quite near.
Related Commentaries of Genesis 1:20
Genesis 1:20-23
20 And God said, Let the waters bring forth abundantly the moving creature that hath life, and fowl that may fly above the earth in the open firmament of heaven.
21 And God created great whales, and every living creature that moveth, which the waters brought forth abundantly, after their kind, and every winged fowl after his kind: and God saw that it was good.
22 And God blessed them, saying, Be fruitful, and multiply, and fill the waters in the seas, and let fowl multiply in the earth.
23 And the evening and the morning were the fifth day.