What are the little bugs in my aquarium? - Seed Shrimp (Ostracods)
These little bugs are a type you are almost certain to see eventually if you keep shrimp, at least if you keep shrimp in a tank without fish. Like the Cyclops (copepod) these little bugs are harmless to the shrimp or any fish you might have in the tank. The fact that they are there is typically considered to be a good sign as their ability to live and reproduce means that the water conditions are right for them (and by extension, right for your livestock too) They can be ugly and gross if you aren't fond of bugs, bu they won't hurt anything.
You can ignore them, or you can feed them to your fish, or just cut back on feedings in that tank and they will starve out eventually. The much bigger shimp will always get to the food first.