Critters in substrate?

[IAmGroot420]

brand new to reefing here. Started my 1st saltwater tank 2 months ago. Started with Live Rock and added macro algae, 2 clown fish, conch’s, anemone, and two corals. 20 gallon tank.

I just noticed today small critters in substrate. They look shrimp like. One is green, a few white, and one orange like color. Any idea what these are? I attached a video to this thread

 

[IAmGroot420]

I wasn’t able to view my video, so I attached photos

 

[Idech]

The best for videos is to upload to YouTube and link it here. I can see your video but most people won’t.

Some look like bristle worms but one worm in particular looks like it has antennas so not sure what type of worm. Look up bristle worms and amphipods to start.