Spiky critter

[John A!10]

Hi I just noticed these on my live rock does anybody now what they are?

 

[James M]

Hydroids

 

[John A!10]

Hydroids

What should I do should I put glue on them.
Harmful?

 

[saltyfilmfolks]

Yup. Putty n glue. Can sting fish. Can spread.

 

[John A!10]

Yup. Putty n glue. Can sting fish. Can spread.

Ok thanks it has only spread a tiny but in the past two weeks as in the beginning I thought it was part of the rock.

 

[Shaina Carey]

Freshwater tanks get something similar to that called hydra. Before I looked at the other comments, I thought hydra, lol