algae?

[tab]

Just wondering what this might be. It's been in our tank since we bought this piece of live rock and it has grown tremendously. Hopefully it is not dangerous to anything, although I guess if it was we would know it by now.
It also survived the March tank crash...

http://i17.photobucket.com/albums/b84/tabtrask/DSC_0011Medium.jpg

[blueboy]

looks like sponge to me

[erikharrison]

thats kinda what we thought, but is it good, or bad?

[blueboy]

it's a filter feeder, good just for bio diversity, and some fish LOVE them.

[Richard]

Cryptic sponges are great for filtering your water and removing organics from the water. Let me know if you want to sell it.