What Is This?

Got some blue velvet shrimp from friend who was moving. Got home and saw few of these specks moving around. Next day there are a lot more. What are they? Will they harm fish?

 

Copepods, Totally harmless. They come and go occasionally in both of my tanks.

 

Look like ostracods - seed shrimp in your photo.

 

Harmless micro-fauna, your fish would love those as a fresh meal. Take some and let them breed in a separate container, preferably a bucket outside, you would have limitless fresh food for your fish.