ID Please

[Chin_Lee]

I've got this thing growing on one of my rocks. Does anybody know what it is? Its soft and sways with the current...
http://www.canreef.com/photopost/data/500/236104_0443-med.JPG
thanks

[Quinn]

Looks like a sponge, don't know if there are any species that would be that flexible though.

[ungp]

Is this stuff harmful?

Looks like a sponge, don't know if there are any species that would be that flexible though.

[Quinn]

The proper term would be "these things", as they are animals, like corals, and as far as I know, generally they are not harmful. There are a few species that in fact bore into stony corals, but I do not know of anyone who has encountered them. More typically they have specific feeding/environmental requirements and die in aquaria. Some species do thrive, obviously, but sponges are not known as a choice for beginners.

An interesting quote from Bob Fenner: "...if you find the Orange Icing Sponge, Mycale laevis growing under your plate-type corals, this is not a 'bad thing'. This Sponge actually protects the Stony Coral from Boring Sponge infiltration."

http://www.wetwebmedia.com/sponges.htm

Chin_lee, does that thing have any visible polyps? I wonder if it could be some sort of soft coral?

[Chin_Lee]

Thanks Teevee... i think i found what it is from that link you provided
http://www.wetwebmedia.com/spongesiii.htm
It looks like:
Leiodermatium sp. Wavy Cave Sponge. Hard to the touch and distinctive in shape. Found in caves, within crevices. May be endemic to Hawai'i. Kona pix.
And sorry my mistake, it does not sway with the current ..... one of the piece is just not attached very well and so moves with water flow but the rest are stiff.