I love this tale (or should I say tail haha). The rhyming and flow was consistent, and I liked the happy ending, as I expected him to encounter a siren or someone who would try to lure him to the bottom of the sea. I always enjoy poems with that fantasy twist and who couldn't love mysterious creatures in the sea, especially mermaids?
Two small things:
Second stanza: "But as gasped to take a breath"
- Should it read "But as he gasped to take a breath"?
Fourth stanza: "Your lifes still incomplete"
- Apostrophe needed! Should be "life's"
Welcome to this site, by the way! Hope to read more from you soon.