That looks close, but it isn't a copepod, at least like any I've seen. It must be some sort of snail or worm. I just took another look and saw some other critters too. I just saw a snail (tiny, barely noticeable shell), and something else that I have seen from time to time that looks like a tiny jelly fish. It is bell shaped and resembles a snow flake. I have seen these swimming around before. They propel themselves just like jellys. Any thoughts?
The original creature in question is still a mystery. I have been searching databases, but I really don't have anything to go on.