Trying to figure out what this is....

[Rsbritt27]

Hello my tank is only about 3 months old...I am trying to figure out what these things are growing out of my rocks. Anybody have any idea what these are? I have attached 2 pictures. Thanks!

 

[Lionfish Lair]

The first is an appy, you'll want to remove that.
The second is a feather duster, that's fine to keep.

 

[Rsbritt27]

The first is an appy, you'll want to remove that.
The second is a feather duster, that's fine to keep.

Is the appy harmful to my fish? Thanks for replying by the way.

 

[Lionfish Lair]

They do sting, but I've had my fish sit on them and not react, so IMO, they are fine in that regard. They grow out of control, though, and probably will reproduce better than anything in your tank. It's much easier to remove one now, than deal with a mess of them later.

 

[Rsbritt27]

They do sting, but I've had my fish sit on them and not react, so IMO, they are fine in that regard. They grow out of control, though, and probably will reproduce better than anything in your tank. It's much easier to remove one now, than deal with a mess of them later.

Thanks for your help!!!