Coral id

Bought a zoa yesterday, what's growing between it?

 

Colonial hydroids

 

Colonial hydroids

 

Thanks, is this something I need to be concerned about?

 

Yes they are an invasive pest that spreads quickly. I would pull that frag and quarantine while you try to get rid of them. Manual removal attempts in the tank will probably only hasten the spreading process. There are some critters that reportedly eat them but that is always a hit/miss option. Some people have used a kalk slurry or covered them will 2 part epoxy but your case means wiping out most if not all of your zoa's in the process if you tried that. Your best bet is get the rock out and manually remove them from between the zoas and quarantine it until you are 100% sure they are all gone. You'll lose some polyps but if left in there you'll most likely lose your entire tank eventually and the hydroids will out compete the polyps sooner than later anyhow. Sorry to be a bummer.

 

Ok thank you for the information.