Sink or Swimchesters Merkids

This is from chapter 2 when Sammy had just hatched with a little help from his big brother!

their nest site was scratched out of the side of a cliff by their gigantic parents. It's bordered with kelp for stability and softness and the floor of the nest alcove is sand. When Sam first emerged he wiggled his tail fins so much in Dean's arms that sand billowed up around them. Dean wiped off his baby brother, announcing that "Baby is sandy" aloud which his parents heard as "Baby is Sammy" due to how small he was compared to them and his slight slurring of words. Dean's not much older than Sammy, so he has trouble holding the squirming bundle of fins.

For size reference, since Mers get HUGE their babies start off relatively minuscule compared to them, here, Dean as a toddler is about the same size as a full grown human. Sam's about the size of an eight year old.
They grow fast for the first few years up to the double digits in length then slow down to about a foot a year. So Sam at 200 years old is about 210 feet long in the other pic when they meet again after two centuries apart.

I had a request to do the brothers as kids and I had a lot of fun trying to figure out how Dean should look. going back to the descriptions because it's been so long since I wrote it down! All I could picture is that his coloring resembles the Dragon!Dean version of Dean. dark brown mottled to tan with freckles everywhere. I'd done Sam's pic as a gigantic adult first (What spawned all this in the first place was that picture for MerMay like a year and a half ago!)

the story can be found here or the whole thing on Archiveofourown.org