Id this please

[no1bubba]

I noticed that my Duncan has not been opening for several days I turned it around last night and found this. (Pic). It probably isn’t the problem but I don’t like it growing up into Mr. Duncan. What is it?

[mcgyvr]

I can't tell from that pic.. Just looks like some algae..

[no1bubba]

Ok, thanks, guess I’ll find something else to stress about

[Oldreeferman]

LOL, I hear ya about another thing to stress over, that does look weird has me stumped ive not seen that before. Long as it does not spread i wouldn't loose sleep over it but if it does start to spread id start dipping corals or put in a QT tank.

[jlmawp]

Looks like a white-ish sponge that has a lot of detritus/sediment on it.