After four days of creation, God had set the stage for life. The earth was green with grass, plants and trees. The expanse of space was decorated with the stars and planets. The water and the solid ground were established. The next phase of creation filled the seas and the air with life. God created the creatures of the sea and the birds in the sky.
The fifth day was the start of true movement on the earth. God prepared the waters and the skies for the eventual arrival of man. The beautiful, useful and sustaining specimens of life created on the fifth day served as inspiration and sustenance for humanity.
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.