ID?

[boyer.michael.s]

What would this be. It was on a drag plug from a recent order I received. It survived coralrx dip. It’s brown but slightly translucent and flaky. TIA.

 

[ISpeakForTheSeas]

I’d guess a macroalgae of some kind.

 

[vetteguy53081]

What would this be. It was on a drag plug from a recent order I received. It survived coralrx dip. It’s brown but slightly translucent and flaky. TIA.

Pics on a paper towel with ambient light often makes it hard to tell. Anything moving?
If not, can be as simple as algae, sediment or plant material (which often does not fall off in a dip)