WHAT IS IN MY TANK

[morganolivia]

I was doing a water change when I noticed a worm-like creature crawling out from a live rock. I just purchased a pink sea cucumber a week ago and I’m wondering if it was pregnant, considering this small animal resembles my sea cucumber. Of not, then what is it? Please help! I’ve attached a picture of the small unknown animal, and my pink sea cucumber.

 

[JasonK84]

That looks like a fire worm. Possibly a regular bristle worm. Definitely not a cucumber baby.

 

[Lovemyreef2015]

It's a common bristleworm. Good cuc