bristle worm?

Hello Reefers! Looks like I found a new little tank buddy. Fortunately, he's in a small tank that only has about 8 pounds of live rock that came from a local tank breakdown. It started to get some nuisance algae so I took it out of the tank it was in with a bunch of coral frags, and sent it to...

I recently had 2 fish disappear so I went to check the back of my tank to make sure they didn’t make their way back there, but instead I found these worms. I have regular bristle worms in my tank, but I’ve never seen them with tentacles/ hairs this long that go from red to white tips. Any ideas...