Does that happen to anyone else?

[Notsolostfish]

I came down to my tank, to find one of the nicest big hammer colonies i had over a year one of the heads polyps deflated like a balloon, and got me a bit nervous, i don’t know if that happened after i fed the tank, and my hippo tang swiped it since he swims fast.

Alk: 9.6
Cal:470
Mag:1410
Phosphate:0.11
Nitrate:12.5
Ph:8.2

 

[56longroof]

Yep. I have 4 hammer corals in my tank and one of them completely receded into the skeleton. It's finally coming back but slowly. The others look great.