What are these little guys I found in my tank filter

[Andie]

When I was putting new filters in my tank I noticed these little guys all over the filter of my tank. I tried uploading a video but it won't work. They are alive. They move around. What are these? I'm very new to the saltwater world. When I started my tank I got water and rocks from from active tanks so all these creatures I'm finding probably came from that.

 

[budblue]

amphipods

 

[monique]

amphipods, copapods-good

 

[budblue]

they don't do any harm in my tank :)

 

[Becky]

Hey there, just wanted to say welcome aboard @Andie! :thumbsup: