Help Indentifying - worm

[slp0923]

This little bugger decided to pop his head out over the weekend. I startled him and he quickly went back into the rock.

Noticed him again in the same spot and was able to get a picture.

Any ideas what he might be?

 

[Sugar Magnolia]

Looks like a bristleworm. Very beneficial.

 

[ReeferBill]

Plus one on the bristleworm ! They will self regulate themselves depending on amount of feeding and nutrients!

 

[Betta132]

Harmless bristleworm, just don't touch. It'll sting you. They clean gunk up and stuff, and they'll multiply like crazy if you feed too much. If there are too many, you're overfeeding.