What is my umbrella mushroom doing?

[matt2364]

My umbrella mushroom will sometimes close up, like the in the picture below. When it re-opens the mouth area, the mushroom is usually white and inflated a bit. What is going on?
At the very bottom is a picture of the mushroom a few days ago, before I moved it.

 

[zeroc]

eating or it's just mad at the moment.

 

[h2ocrazy]

Yep, it is either eating or feels bothered. Here is a shot of my frilly mushroom eating some chunks of silversides.

 

[debbie]

Yep, it will be eating. When I feed frozen foods in my tank, my mushrooms will close up like this as the foods fall onto them they will do this.