What is this?

[curtis12282]

I found some, what appeared to be, reddish brown (more brown) slime. It is creeping over a piece of live rock it is very smooth and soft looking but hard to the touch. During mid day it looks like it is cracking open but when the lights go out the cracks get smaller and the possess repeats when the lights come back on the following day. I am just wondering if anyone knows what this stuff is. It looks like it could eventually cover entire live rocks and smother them out.

 

[tlk]

Sounds like Red Slime Algae (actually a bacteria). JustinX wrote an article a while ago on this topic. I followed it and got rid of it withOUT using any chemicals. Off the top of my head, I cannot recall the article, but my thread was called "my algae problem". He listed the article name there, you can then find it and apply it.
Good Luck!

 

[birdy]

If it is hard to the touch then it isn't red slime algae, cyano is slimey and if you touch it, it will be all over the place. I am wondering if it is not some sort of encrusting sponge, but I don't know if they recede or not, mine doesn't seem to, I will include a picture of mine (not a very good pic, it's from a digital camcorder)

 

[michaeltx]

sounds like a sponge of some sort I have several different colors in my tank. here is picture of a grey one. but most are harmless there are a few that grow this way that I have heard can overgrow a coral skeleton.
Mike