What is this? Identification.

[ozzyjazz]

I got this colony of white thread like stuff growing on one of my live rocks. I thought it was just some dead stuff left over but it seems to be growing now. I wonder if anybody knows what it might be, if it poses any threat to anybody in my tank etc.

I have a couple 2" tangs, a yellow coris wrasse, a couple little false percs and several 1"-5" mushrooms. I also have two cleaner shrimp, a tiger pistol shrimp and his buddy, a black ray goby.

The tank is 50 gallon with a 30 gallon sump. :idea:

 

[billsreef]

Looks like some kind of sponge. Nothing to worry about.

 

[Ixodes]

Yup, a sponge.

 

[Betta132]

Thirded, it's a sponge. Totally harmless. There's a slight chance it could start growing over corals, but if it does you can just pluck it off.

On an unrelated note, a 50g is too small for tangs. They may not show aggression now, but it'll be an issue when they start getting bigger. I'd suggest removing them and adding something else, maybe a dwarf angel of some sort depending on what corals you have.

 

[ozzyjazz]

Tangs in a 50ga

Tangs in a 50ga

Yeah, I knew they would only be able to live in the tank for a couple years. Another guy was at my LFS wanting to give the Sail-fin to them for nothing so I offered him $5. I'll trade either or both of them when they either start getting big or aggressive.

Thanks for all the replies about the stringy stuff. Sponge makes sense. It is growing but only very slowly so I won't worry about it.

 

[lu9103]

Yes thats a sponge alright, just keep an eye on it.