Featherdusters or Hyrdoids?

[TKEON230]

I have some new things growing in my tank that I'm not sure what they are. They kinda look like a cross between a featherduster and a hydroid. I have a couple pictures of them here:

Are they bad for the tank? If so, any way to get rid of them?

 

[Sadielynn]

they look like colonia hydroids ... I have them and they have not spread from where they are ...they are pests but I have not found a way to remove them successfuly (at least in my tank ) I have tried scrubbing them and such and may try joes juice when I do a larger water change in the future ...they can sting corals and kill them off ...but do not walk around if that is any consolation .... In the upper picture you have also green bubble algea , when changing water siphion it off and out try not to break the bubble if possible as it will release spores .... HTH

 

[Kurt_Nelson]

Yup... colonial hydroids, for sure.

You can try and kill them off by plastering the area over with a thick mixture of kalkwasser and water. That has worked for me in the past. Just don't do too big of a patch at one time and don't get the paste on any corals.