Worm ID (thousands of them!)

[Gatling]

I turned the flow off for my 20 gallon tank to feed some LPS when I noticed a bunch of worms suspended in the water. I'm not exaggerating, probably 1000 of them. Here's a photo from the tank

And here's a microscope picture of one:

I have 1 cardinal fish that has shown no signs of parasites. This worm probably isn't causing harm but what is it???

 

[DSC reef]

Only thing that comes to mind is spionid. Typically the form a tube with mucos in the sand bed

 

[tuesdayd]

@KJ - he's always got the answer!

 

[KJ]

Spinoid worm harmless .

Figure 10. Phyllochaetopterus sp. Left: Animal in the tube with its tentacles extended. Right: Animal removed from the tube. Note the small regionated body and large tentacles.​