Please identify, aiptasia?

[Dalton]

This popped up in my tank a few weeks ago and is spreading fast. No coral in there yet so I'm not worried about that but I need to identify it so I can get rid of it.

 

[Kano]

I spy a hermit crab, rocks, and sponge. No need to get rid of it.

 

[occ_motorcycles]

Yeah just a lil sponge. Not harmful unless you over feel alot and give it tons of nutrients. (Just maintain you tank like ya should and you will be fine.)

 

[Dalton]

Thanks. I thought it might be but its spreading to well lit areas so I wasent sure.

 

[Steve175]

Definitely not aptaisia and definitely benign. One of the many cool, free things that will pop up out of nowhere (my favorite part of the hobby).

 

[GratefulReef]

Yes, I have a bunch of this sprouting up as well, along with a darker and thicker sponge that grows slower and actually is growing around the stem of some button polyps