What are these? Tiny swimming worms?

[mstockmaster]

I was looking in my tank shortly after lights out tonight and saw what looked like particles drifting in the water, then realized that there were something swimming against the current. They were attracted to the light on the glass. I was able to get some pics and a video.

Sorry for the poor closeup, it was taken through a 10x magnifying glass and was hiding behind the edge of the silicone, it was the only one sitting still.

I'd say at most they were 1/8 inch long. I can link a video if needed.

 

[mstockmaster]

Video

https://photos.app.goo.gl/NknNOR6grB9PuRwO2

 

[Maritimer]

They're the epitokes of polychaete worms.

Harmless - reproductive, IIRC - and often considered tasty snacks. By fish. Not by me, I don't eat 'em.

~Bruce

 

[mstockmaster]

That's kinda what I thought. Weird thing is that I didn't even know I had any worms in the tank to begin with. Something new every day...

 

[Gyerfat]

I just noticed 2 of these swimming in my refegium. They are about an inch to 2 inches in length and swim around pretty fast. I didn't notice any bristles, they look smooth. Gonna try to get a closer look and a picture. Glad to hear they are not bad.