What are these?

[Reef Monster]

So I'm in the process of a tank transfer and while breaking my current tank down I found these critters. Can someone tell me whether I should keep or remove. My tank has only been up since February of this year.

 

[Crabs McJones]

Top picture looks like a medusa worm, bottom pic im not sure, can you get them out of the sand and into a clear plastic container for better pics?

 

[Reef Monster]

Sure! Here goes:

Should I keep any of these?

 

[stanleo]

First one looks like a medusa worm, second one looks like a fireworm. Its your call. Both are harmless though they can become unsightly if they over populate and the fireworm can cause some nasty skin irritation. They can be helpful little CUC critters.

 

[KJ]

Sure! Here goes:

Should I keep any of these?

Hard to tell from the pic @Lovemyreef2015

 

[Reef Monster]

I just found this worm from hell...

Seems to be the mother of the worm in the first picture.

 

[KJ]

I just found this worm from hell...

Seems to be the mother of the worm in the first picture.

Medusa worm (Sinaptidae). Good CUC!

 

[Reef Monster]

Should I keep the medusa worm if I have hermit crabs in my CUC? I read they can secrete a deadly toxin if messed with.

Update** I just checked my rocks and there are medusa worms everywhere. I just recently had a bunch of fish die too so now I'm not even sure what to do at this point. I have the remainder of my fish (Hippo tang and and yellow prawn goby along with my CUC) in a quarantine tank right now. I'm seeing conflicting information online regarding these cool devils.. =/

 

[Lovemyreef2015]

Sure! Here goes:

Should I keep any of these?

Looks like a type of pollycheate just can't tell much with the photo provided.