Word for Word: Episode 45
On the other side of the spectrum of sea creatures were the myriad of smaller animals--living beings that self propelled through the water, the liquid medium that makes life possible.
There are so many different sea animals that we may never know how many there are or may have been. They live in the deepest part of the waters that have been explored so far. They also live in drops of water so small that the air can transfer them to bodies of water far inland. (see https://massivesci.com/articles/sea-spray-microbiome/)
Aside from the placement of the stars, the filling the ocean was the most extensive act of original creation. And so far as we know, this collection of living things far exceeds the stars in variety.