Know what these are?

[jnslondon]

I have noticed about a dozen on my rocks, snail? But they have a whole with feather things out the end.

 

[fort384]

Where are we looking in the pic? I see a lot of things there

Based on your description they sound like spirorbid worms which are harmless.

 

[Crystal A]

Pineapple sponge. It's right infront of the zoa fort. It has green Algae growing on it hard to find. They are harmless filter feeders a normal part of a tank establishing itself.

 

[fort384]

ah I see it Thanks crystal.