White things w/ tentacles attached to rocks

[biglittlehoss]

I am trying to figure out if these white things attached to our rocks and have tentacles are the things that I don't want in my tank. Seems like they are spreading kind of fast, and if they are not good, I want to eliminate them before they over run the tank.

Thank you.

[Max]

it's either a vermatid worm or atapsia "or probably so anyway".

[sapgranth25]

is it just a white tentacle are two coming out of your live rock with no body attached? if so you may also notice that there is bits of your sand stuck to the live rock kinda like a small tunnel if so there harmless just another live rock bonus they seem to pick bits of gravel/sand up clean it they also eat waste

[zebra unagi]

hi there if its the same thing i had in my tank when i started it off they are snail lavae, the best way i can describe what i had was almost like a cressent moon shape stuck to the rock and it has 2 feeder appendages, it throws these out in to the current and then retracts them periodically and is a whitey clear colour . my lfs told me they were nothing to worry about. if they are not what i have described then i hope others can help

[biglittlehoss]

I think I've discovered it's a atapsia. I have used lemon juice as suggested on a couple of threads. It works like a miracle. At least they appear to be gone so far. I'll keep an eye out for more. Thank you.