Help to identify please

[MarkDarnell]

These white "things" have popped up the last few weeks in my corner overflows. What are they? Are they a problem that I should be concerned with? I see very few of them in the tank, but alot in my overflows.

 

[kschweer]

They are pineapple sponges. They are harmless.

 

[143MPCo]

Agree they are pineapples sponges , it's a good sign of a healthy tank.

 

[MarkDarnell]

Thanks all.