White dots, copepods?

[Icryhard]

So I had bought rocks/stones from my fishstore and he stated that he had copepods in the sump (where the stones were). Looking at my aquarium glass I have a lot of tiny white dots. I don't know what these are. I somewhat am hoping copepods, but I doubt it. See the picture for reference.

 

[Zach B]

Hydroids

 

[Zach B]

They usually go away on their own as the tank matures. Best of luck

 

[Icryhard]

They usually go away on their own as the tank matures. Best of luck

That's unlucky. I was really hoping for copepods. Do they cause any harm, or are they for that matter useful resource for fish?

 

[Cthulukelele]

They are mainly an early tank transitory hitchhiker. They aren't really food for most fish and can sting corals, but these aren't the hydroids people are usually complaining about taking over their tank and stinging everything. Also if you've got hydroids proliferating you almost certainly have pods proliferating too. Keep an eye out you'll see them.