Actually I don't even think they are supposed to be representative for baby mermaids, but just some kind of really small mermaids. Young ones nontheless (see the hilarious bubble swimming aids). But since they were so small and so many of them I immediately pictured them hatching from eggs. And it made me wonder for a sec how mermaids actually procreate.
Then I remembered Kokoro, and her story with a human man so it must probably work the oldfashioned way…
Guh, I hope I haven't grossed you out too much...sorry.
Maybe mermaids can only procreate after they`re over 30? And yes, you did gross me out