White Film around stem

[miggyjg]

The stem of my hammer has a white film all around the stem and on the plug not sure what it could be any ideas ?

 

[Gumbies R Us]

Maybe a sponge?

 

[ISpeakForTheSeas]

Yeah, tough to say for sure from the pics, but a sponge would be my first thought too - as long it doesn't start growing over the coral's polyps, it should be fine/harmless (sponges can grow around the stalk/stem without issues).