What worm is this?


New member
Found this in my tank yester day it must have been in the rock which i bought in august 2005???? - red with a white stripe running down center. Head looks white for about 1/2 inch, looks like 2 tiny black eyes on it. Posted a few pics, have more if anyone wants to see.



Looks a lot like a bristleworm of the harmless sort, ie, a Pacific: when they're out of water, the bristles tend to collapse a bit, but the one where it's in water looks like bristles. They're detritus feeders.
That's an epitoke of a polychaete in the family nereididae. Epitokes are worms that have become modified in order to spawn. In this animal the anterior paler region is normal but the reddish middle & posterior has enlarged and the parapodia ("legs") and bristles have become larger & fan like so the animal can swim into the water to release its eggs or sperm.
There are thousands of different types of polychaetes and they come in all sorts of sizes & shapes. Bristle worm is the common name for just one small group of polychaete worms known as amphinomids. The one in your images is probably a nereid. There would have to be both males & females in order to have babies.

And yup, that's me mentioned on the Cal Academy page. I help them out with worm questions.