What are these living in my sump? Looks like sponge with a filter head?

[SomeWobbles]

Hello everyone, there are about a dozen of these living in my sump attached to the glass. What are these? Are they harmful?

 

[NeedAReef]

Pineapple Sponges?

 

[WalkerLoves_TheOcean]

They look like pineapple sponges, which are a good thing to see.

Harmless filter feeder, and signs of a mature tank.

 

[EeyoreIsMySpiritAnimal]

They look like pineapple sponges, which are a good thing to see.

Harmless filter feeder, and signs of a mature tank.

Actually, they're usually found in new tanks... Not necessarily a sign of a mature system.

 

[EeyoreIsMySpiritAnimal]

Hello everyone, there are about a dozen of these living in my sump attached to the glass. What are these? Are they harmful?

Lots of good info in the sticky threads.

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

 

[vetteguy53081]

Indeed Pineapple and often silicates are a cause. Can be from new rock, new sand, from tap water if used and expired or leaking Di Resin cartridges.
These are short lived and will dissipate as silicates reduce. You can peel them off with the edge of a credit card into a net if they are too many
They are not harmful and cherish algae if they get any

 

[WalkerLoves_TheOcean]

Actually, they're usually found in new tanks... Not necessarily a sign of a mature system.

Sorry, I got it mixed up with something else.