No clue what this is

[paulr]

So i found this white stuff on a rock. It is white and is somewhat transparent. Seems like some movement. I got this rock from an established tank. Doesnt seem to be causing any harm but not sure if i need to get rid of it.

 

[amanda_marie]

Looks like sponge to me, harmless.

I had some that looked identical on some rock I placed in my tank after curing in a covered 5 gallon bucket for some time.

 

[paulr]

Is it a type of coral then? Tank has only been up for 12 weeks so dont think i would see much growth.

 

[amanda_marie]

No not coral.


The sponge that showed up on my rock did so in no more than a months time while the rock was curing.

Sponge Hitch Hikers

May be of some help
Aquarium Invertebrates: Sponges, Phylum Porifera — Advanced Aquarist | Aquarist Magazine and Blog