Tube Anemones Maybe help me out

[KidCNU]

I went on vaction for two days and didn't touch my tank and i came back and i found these tubes growing about 3 in total two pictured they are brownish with green speckles inside they have no tentacles that come out of them and they retract into themsleves with a little hole left when touched any idea i thought they might be feather dusteres at first which i found in my tank but they have no feathers and look way diffrent if anyone could help me with what these are??? if you need more info i'd be glad to give what i can

[janasleah]

They almost look like zoas...but the pic is so fuzzy, it's hard to tell.

[oscar5453]

Coral they seem.

[Paula]

So, are the tubes hard, calccareous? Do you see a tiny web or string extending sometimes? Looks like a little creature is inside? If so, would be vermetid gastropods. Like snails, they build these little tubes with calcium in their mucus. The web, string is mucus, and the gastropod uses this to go fishing for food. They pull in their net and eat their catch along with the mucus - yum! Harmless little things, are great to watch, I love them! Hope that's what you have!

[reef hugger]

They look like Protopalyothoa or possibly Zoanthids. New Proto polyps don't have very noticable tentacles until they get larger or maybe there is something in your tank that is bothering them and that is preventing them from extending their tentacles.