They are likely copepods or newly hatched amphipods, both of which are harmless little crustaceans that regularly occur in FW, brackish, and marine environments. Many fish eat them and they are good detritus eaters.
Ok cool. Have had aquariums for years now... never seen them... lol they jump across the water and hang out on the glass. Im sure my loaches eat them when they are in the water. thanks for the quick reply!
Oddly enough I had never had them in freshwater until very recently. They hitchhiked in on some plants I purchased. My scarlet badis love them! Of course in my reef tank I have literally 1000's of them. They come in different types and are lumped into the nickname "pods".
Here is just one species under magnification. What you have may differ of course.
Very interesting indeed! Mine have little legs and look kinda like ants on a micro level and white. If they are harmless to my fish and plants im happy!