Hitchhikers ID please, are these good or bad

[reefpot]

Hi,

Please help me identify these hitchhikers. They are growing in 3-4 different areas separately. I want to know if they are harmful. Thank you.

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[AaronM]

First pic maybe a ball anemone - not harmful.

[reefpot]

Thank you.
Very concerned if the second one. Read somewhere that it could spread quickly and I need to take the rock out and brush it off. Please help.

[noahm]

+ 1 on the ball anemone. The second one is tough to tell. Does it open up or anything? As it is, it looks like a sponge which i wouldn't worry about. Just a guess though.

[reefpot]

Thank you.

The second picture that looks like a mean sponge doesn't open and has those little tentacles sometimes and it started as one and now I see about 6 of them over the last month and they are just smaller than a dime.

Sam

[reefpot]

As I observe closely I see more of the ones in the first picture almost on every rock. Please let me know if I need to do anything. I also see a lot of small feather dusters orange feathers on most rock. Is that anything that I need to worry about. Thank you in advance for any help.

Sam

[Mitchgams]

feather dusters are good they are filter feeders and they're pretty