What is this white stringy stuff on my Firework Clove Polyp?

[One Reefing Boi]

as the title suggests, what is this stuff growing on my firework clove? The heads are happy and open but they have been dying off one by one since I got it about a month and a half ago. I have another FCP a few inches over and it is perfectly happy and doesn't have this stuff and is growing a few new heads.

TIA

 

[Snoopdog]

Looks like hair algae to me.

 

[One Reefing Boi]

Looks like hair algae to me.

would it be causing the clove polyp to die off like that?