Fin rot related to this...weird stuff?

[Lardeelion]

I noticed my son's betta has a mild looking tail fin rot today, or I assume it's fin rot. He's in a 5.5 gallon by himself with plants and a sand substrate. The only variable is this weird fuzz/mold/fungus on the driftwood. It's a new piece in this tank, but I had it for years in my 55g. It dried out for a few months before I decided to slice it down to a size appropriate for this wee tank.

Could there be a connection?

Ammo 0
Trites 0
Trates <.5
pH 7.4

Commencing water changes for Mr. Betta before I start with meds.

 

[tamtam]

To my knowledge it's harmless. I've had this pop up on my drift wood a time or 2. Much like algae it often goes away on it's own. I'm not sure if it's a type of fungus or what but have read that snails enjoy it.