ID please. From the darkness they came.

[butesch]

So not sure what this is popping it's head outside of a small dark hole in a rock. I remember seeing it a while back when I started my tank and I was fighting aiptasia at the time. Thank you Berghias! I thought I nuked this as I thought they were a type of hydroid. Apparently 1.5 years later they have lived and are coming out to play again. They have a brown stalk and a green head with small tentacle like stuff around it.

Are they are hydroid of some sort?
Should I destroy them before they destroy me?

 

[Moeshi]

So not sure what this is popping it's head outside of a small dark hole in a rock. I remember seeing it a while back when I started my tank and I was fighting aiptasia at the time. Thank you Berghias! I thought I nuked this as I thought they were a type of hydroid. Apparently 1.5 years later they have lived and are coming out to play again. They have a brown stalk and a green head with small tentacle like stuff around it.

Are they are hydroid of some sort?
Should I destroy them before they destroy me?

Hydroids. They can take over if conditions are favorable. Most noticeable they are able to sting corals to death.