Sponges or ?

[BanZI29]

Are these sponges? Are they good or bad?
Please and thank you!

 

[KrisReef]

Sponges, maybe tunicates? I don't think they will harm anything either way.

 

[BanZI29]

They seem to be spreading. When should I be worried?

 

[Mastiffsrule]

Sponges are good, I would not worry.

 

[Double monti 61]

Yes and in a well balanced system their numbers should decrease and become a part of system not a problem I have some purple ear sponge that grew large and started to shade the coral below it so I cut it out with a small pair of scissors and it did not show itself for a while but has started to grow back I do not plan on removing it again since some of the coral in the tank have grown larger and so far they seem to grow together but if the ear sponge starts to overtake the coral around it I will remove it I also have another sponge that is no problem and lives on the rock below the coral ,on my substrate and some that grow on one of the holders of the water heater

 

[Emanuel Refer]

Probably a: Clathrina.sp sponge.
Nothing to worry about.
They are actually pretty useful in a reef system.

 

[G Santana]

I have a ton of those in my tank now, always thought that they were an indicator of a healthy tank.

 

[bnord]

I have silicates get through my RODI system (well water) and so I have sponges who thrive on silicates
would rather occasionally pluck them from where I don't want them, than have high circulating silicates

where did you get your rock?

 

[Timfish]

Sponges, very beneficial, they are essential recyclers on reef systems and process DOC 1000X faster than the bacterioplankton removed by skimmers as well as nutrients.