• Someone a lot more biologically inclined than myself could (probably? if indeed such short-lived organisms exist?) give examples of fast-reproducing organisms (microbes, gnats, etc.?) whose life-spans are only a few hours, and thus would have died on the same day of their creation.
• According to ‘mature creation’ theory (creation created ‘mature’ – light already in transit from distant stars, trees with [very misleading!] annual rings only moments old, etc.), there would have been very, very ‘mature’-slash-about-to-die birdies and fishies created, some of which – conceivably – would have died on the same day of their creation.
• Also, unless not one, single, fish-eating bird dipped down and tasted of the delicious bounty of the shimmering little fishies below, at least some fish would have died on the same day of their creation.

Beyond conceivable doubt, even given a 24-hour day understanding of creation (with 6, successive acts of ‘spontaneous creation’), there would have been physical death before the events of Genesis 3.

((note: I see no reason to doubt that the text of Genesis 1 was originally a poem/song expressing theological truths, as opposed to being a play-by-play, moment-by-moment, fact-by-fact account of the ‘how’ of creations’ origin.  Thus, the nit-picking-ly detailed exercise above ought to be unnecessary – but is merely noted in reference to those who insist that there could have been no death before the Fall.))