Honestly, just because I don't think it was relevant to mention it. If you read the account of Genesis 1, it also doesn't mention the creation of water. It says that God created the earth and the the Spirit hovered over the face of the deep. We just assume (rightly) that water was also created when the earth was created. And water is far more necessary for survival than fire.
It also doesn't mention the creation of Oxygen, which is more necessary even than water (although I suppose you could rightly argue that they are as vital as one another, just that you would live for slightly longer without water than you would without oxygen). There is a record of the atmosphere being created, but no mention of making it breathable. That is just assumed.
In like manner, we know now through observation of the sun, that the creation of fire must be assumed for the sun to be as it is. That is probably as close as you are going to get to a recorded creation of fire.
But to get to the reason, I think it is because the whole of scripture is actually pointing to Christ, and that is it's purpose. So fire is mentioned when it is relevant to that end, but otherwise it is left out. Even if you look in Genesis 1, you see prophetic pictures of Jesus popping up all over the place. The reference to the Spirit of God hovering over the face of the deep (a prophetic picture of a suitable dwelling place not being found for God, a picture expanded on in the dove that Noah sends out from the ark, and then completed with the Spirit descending onto Jesus 'as a dove' at His baptism); the light being created 2 days before the sun and moon were created (showing that it was something far more eternally significant than the light energy produced by the sun, a picture expanded upon again at Jesus death, that as the source of the Light of life was made sin, or darkened, for 3 hours, so also the sun lost it's power to share light); and the sun and the moon to rule over the day and night (a prophetic picture of Christ ruling his kingdom - the eternal day, as it would always be daytime to someone on the same orbit as the sun - and the moon being the demonstration of his Church on Earth - to rule over the night, in other words to be the 'light bearers' of the night [the time between the fall and the second return of Christ] - and the moon only being useful as a light if it is reflecting the light of the sun, just as we can only serve God on earth by reflecting Christ).
The list goes on and on, but in summary and as far as I understand it, specifically recording the creation of fire wasn't necessary to point to Jesus Christ and His Gospel of Salvation, and so it wasn't recorded.
I hope this helps,
God bless :)