Weird white looking fluff on rock

[shmibly]

My tank has been established for 8 months now, and I am just beginning to see this white/clearish fluff growing on the underside of one of my rocks. Getting a clear picture will be impossible. Is it harmful to my fish or corals? Any help would be appreciated. Params are perfect, everybody is healthy and happy

 

[JARRETT SHARK]

Are the feather dusters Maybe?

 

[wschang812]

maybe a sponge

 

[shmibly]

Could it really be a sponge? It blows in the. Current kinda like hair algae would but its shorter. I am worried

 

[basiab]

If it is on the underside it is most likely a type of sponge.

 

[shmibly]

It won't hurt anything though will it? Is it bad to let it grow?

 

[jdnumis]

sponges are a good thing

 

[shmibly]

Will it prevent corralline algae from growing? And will it threaten other corals trying to grow?

 

[jdnumis]

It should not prevent or threaten anything.

 

[KathyC]

As many have mentioned, it is likely a sponge. It is common for them to grow on the underside of rock, and it will not grow out where there is light, so it will limit itself to where you mostly cannot see it.
It will not harm your fish and coralline usually doesn't grow on the underside of the rock anyway. Since you would not be placing corals where it is growing, that should not be an issue either.

If you notice it beginning to grow out in the lighted areas of the tank (very doubtful), post a pic of it.

 

[shmibly]

Will do. Thanks!

 

[LavaToad]

Does it look like this? I had these in my tank a long time ago and they were tentatively ID'd as hydroids. I don't really have any clearer pics than these, and they were from a few years ago

 

[shmibly]

No it doesn't look like that at all...it kinda looks like white/clearish short hair algae thats just hanging out on the bottom of one of my rocks...are hydroids really bad?

 

[stooops718]

Does it look anything like this? If it does then it's a Pineapple Sponge. Which are relatively harmless and most likely go away on it's own.

 

[LavaToad]

I think the hydroids can sting corals, the ones I had disappeared on their own after a while

 

[shmibly]

Nope stoops it doesn't look like that either lol. This sure is a mystery substance in my tank. Its slippery if that means anything.

 

[KathyC]

Sponges can also look slippery.
It would be so much easier to ID this with any pic, even if we can't see much of it, as long as the pic is clear.
If not, can you scrape off a piece (it won't kill the sponge if you do) and take a pic of that?