Have You figured it out yet?
The answer to the riddle is the WHALE.

Fish and creatures of the sea were indeed created before man; whales were created on the fifth day (Gen. 1:20-23), while man was not created until the next day. (Gen.26-31)

God breathed life only into man, not any of His other creations, so only man has a living soul. (Gen. 2:7) Adam gave names to all the creatures God had created in Gen. 2.20

The living soul that God later placed in the "big fish" was Jonah. Jesus himself identifies this "big fish" as a whale in Matt. 12:40. Jonah was only in the fish for a few days when God removed him from that fish. (That's a very interesting story--- Read the book of Jonah for the whole story; it's a short book, only four chapters, so it won't take very long!)

While it is not mentioned in the Bible, it is a well known fact that whale oil was used to furnish light at one time. Of course, the whale had to die for the oil to be used.

By the way, the only four verses in the Bible that mention the whale are Gen. 1:21, Job 7:12, Exek. 32:2, and Matt. 12:40. (This is the authorized King James Version; I can't say about any other versions.)

I hope you enjoyed this little riddle as much as I did, and I hope if you haven't already read the verses mentioned here you will do that now! God's word is full of many such stories and these stories all have invaluable lessons for us today, to help us all to learn and grow as Christians. His word is just as relevent to us today as it was the day it was written!