View Full Version : Strange Grey Fuzz on Rocks

09/09/2011, 09:38 PM
Hey Im trying to figure this stuff out and have not been able to ID it,
it has me worried a bit, doesn't seem like its spreading but I want to know
what it is.




09/10/2011, 09:33 PM
First pics look like beginnings of GHA. 2nd of a pipe & wire also show high nutrients. JMO & GL!

09/10/2011, 09:41 PM
Don't think it is GHA. I have something like this on the underside of my rocks where it is dark. If it is the same thing that I have it branches out at the tips. I've never been able to figure out what it is. Participated on some threads trying to get an answer but nobody could ID it even though a few others had it. I used to have a lot more of it when my tank was newer.

09/11/2011, 12:18 AM
Im very sure that whats on the rocks isn't algae it has no color is somewhat grey. I would say it appears that it might branch, its seems not to have spread to the other rocks. Im told its possibly a sponge of some kind, but I have never seen sponge like that :D

Im debating pulling it and soaking on fresh water for a couple days.

09/11/2011, 03:48 PM
Ok so I emailed the guys on WWM, this is what they say

I have been having quite a time trying to figure out whats growing on one
on my coral skeletons, it resembles green hair algae yet has no color or is perhaps white or grey and seems to branch in some places.
<Mmm, digitate... likely is an algae of some sort... Really need to look at under a lowish power microscope to tell for sure>
Does anyone have any idea what this is? I was told that it may be some
type of sponge but I dont feel that's right.
<Not likely a sponge if very flexible... Algae come in all colours... yours
is likely a blue-green/Cyanophyte... See WWM re, including limiting
nutrient, other means of control. Bob Fenner>

Taino Man
09/12/2011, 01:43 AM
Do you ever turkey baste your live rock off? It helps out in keeping that stuff down. Least that's been my experience, looks like detritus buildup IMO.

05/10/2013, 02:13 PM

I'm having the same problem in my tank. Were you able to identify it? What causes it? How did you get rid of it?

Please help me fight this stuff before it takes over my tank.