Are these a tube worm or something?

[RickysReef2022]

Are these little work looking things bad for my tank? They are one almost every rock

 

[jabberwock]

I believe those are pineapple sponges. They are OK, might clear up over time.

 

[G Santana]

I had about a million of them, as soon as my tank matured they were gone.

 

[Reefer Matt]

Harmless pineapple sponge.

 

[EeyoreIsMySpiritAnimal]

What is that!! A R2R guide to common new tank hitchhikers.

One of the greatest things about starting a reef tank is getting your live rock in and admiring all the diversity within it. The rock comes to life different creatures. This is a guide that I, along with a very well known critter identifier @KJ , have put together for the new reefer on what...

www.reef2reef.com