What is this white stuff ?

[Ingrid]

I bought this wood a few weeks ago from a reputable supplier and now there is white stuffed growing on it . Should I be concerned and what is it ?

 

[FallenPepper]

Did you wash/boil the wood before putting it in? Could be mold, but I had this when I first bought spider wood and didn't rinse it first though it went away after I took it out and scrubbed it

 

[Naughts]

Some spiderwoods can grow a toxic fungus. I would take it out.
Are your fish behaving normally? Is it azalea wood?
I had some from Maidenhead Aquatics that was safe...where was yours from?