ID please - Wormlike, black or brown and white striped

[o2zen]

I have some new Tonga rock in my tank and it was QT'd for about two weeks with nothing showing up on nightly checks.

Tonight I found what looks like a 4 inch long work that was black/brown and white striped. When I flashed the light on it the thing retracted but not crawled backwards so much as melted backwards like I watched the stripes change places as it withdrew itself.

I do not have a photo yet because it is in a very hard place to get to but I will try when I see it again. This rock has been in my display now for about 2 weeks as well and this is the first time I am seeing it.

None of my fish seem to mind it, although I have not seen a peppermint in a few days.

Any thoughts or photos you can suggest and I will try to catch a picture of it.

Thanks. I hate posting without photos but I would hate to leave this be if it is going to harm the tank.

 

[kmk2307]

Try looking up Phylum Sipuncula ("peanut worms"). These are all harmless detritovores / grazers and it sounds like that is what you have. It seems like you have a nice, big one. I would love to see good pictures if you can get them. They retract as soon as you put light on them. I don't believe they can see red light.

Kevin