Anyone have any idea what this is?

[STGTank]

Left this weird alien substance behind in our last tank but now after 2 years its back! Its growing on and around a large rock. Mostly in the shade, but coming out into the light. Its whitish-grey and slightly fuzzy like felt.

Any ideas???

 

[sculpin2]

Sponge. A nice one, too.

 

[tripdad]

Sponge. A nice one, too.

Agree with this. The holes are siphons.

 

[STGTank]

Really? Sponge? its huge! Its taking over a huge rock. So I guess its ok to leave the rock in there. Phew!

Thank you!

 

[Bogue Chitto]

Yes it's o.k. I had one grow in my tank like that and it was yellow orange. It almost covered a good size rock then all of a sudden it started receding and I just have a little of it left now. I am hoping it will grow back.

 

[jraker]

i have two in my tank, one green and one yellow. they are really cool. my largest is only the size of a quarter, though

 

[Dkuhlmann]

Yes an encrusting sponge. I've got a nice size pink one in my DT and several yellowish greenish ones in my sump. Sponges are a good thing, it says your water is in good condition.

 

[Bent]

That is one rockin sponge!