Horn type things growing on my rocks and snails

[mjm889]

there in the middle of the picture

 

[bang guy]

They look like Vermetid Snails to me.

 

[saxman]

The small white critters are most likely Chaetoplerid tube worms...Vermetids are generally quite a bit larger, but it's hard to tell from the photo provided, so it could be either.

 

[mjm889]

are these things harmful to the tank?

 

[saxman]

IMHO, no, but Vermetids tend to throw out a "net" to catch particulates in the water column. Some reefers don't like them because they say the "nets" bother their corals, so it kinda depends on your tank. I had a couple of large Vermetids in my reef, but I never worried about them.

 

[mjm889]

My tank is a fish only tank with inverts, i guess i wont worry then- thanks