White small bee hive looking please is

[STUEYHAWKINS]

Hey everyone I need help I'd ing somethi in my tank. Two weeks ago I saw a small white bee hive looking thing on my coral.  This week I have found 3 more, can you help I'd what it is and is it good, bad neutral or a new coral in my tank

They are about 1 cm high white bee hive looking. Looks like a hollow tube going right down the middle of it and fan type leaves at the opening.  All of them are growing on the underside of my rocks

thanks for all of your help

also if anyone is in the Markham area and have frags or invertebretes to sell I am interested

 

[spyd]

They look like sponges. Completely safe and help clean your water.

 

[TORX]

Google Pineapple Sponge.

I had these as well, they run their cycle, harmless other then they are a bit of an eye sore.

 

[reeffreak]

In my old 75 set-up these things were all over the inside of my oveflow aswell as in between the baffles in my sump and all in the sump they were they for awhile then they all disappeared as the tank matured.

 

[TORX]

... inside of my oveflow aswell as in between the baffles in my sump ...

That is the one issue I had with them, have to be sure they do not clog anything. Mine were in my HOB overflow as well as in my sump. Very little in my DT. I did have to clean out my HOB over flow once or twice because of them