Red Acan randomly shrinks

[Imnotjakeyv]

Just got home from work and everything was puffy and nice, I’ve been sitting here the whole time and and nothing bothered it or touched it in general now it looks like this!

It’s just the one polyp but that one is the biggest one of them all. Do they normally randomly shrink from time to time?
Any ideas?

As I’m typing this a second one shrank up.

 

[GaryE]

Mine shrink up at night

 

[intricate_reefer]

Acans do that. I have a tank with probably 20 or so and some days certain ones deflate one minute then the next minute or day will be fine. If it stays closed for a long time, something is up.