I've had the very same thing as you for over ten years now. They "move" just as yours. They are just floaters, my eyedoc even saw them during examination. They're not a living thing, not parasites or animals.
But of course, if you really believe so, why don't you go for an eye exam, if they can see ordinary floaters, surly they must be able to see things/creatures living inside your eyes. Then you can get drops to instill and probably kill them off in just a day or two.